Add tests for Image, GdImage and Picture - #25

Description
-----------

This is a feature pull request for #1622. It changes the current behaviour of `minlength/maxlength` and `minval/maxval` attributes the way that `min/max` HTML5 attributes will be added automatically if the field is a type of `number`.

I am not sure if the implementation is 100% safe and won't cause any side effects, so any feedback is very much welcome!

Commits
-------

e0194fb4 Allow to set the min/max HTML5 attributes for text form field (#1622)
843fc956 Merge branch 'master' into feature/min-max-field-attributes
96a23e0e Fix the coding style

…#25)' (see #437)

Description
-----------

With @Toflar we have discovered by accident that if a URL is double-encoded (for some reason, doesn't matter) the Contao's `RouteProvider` will eventually throw an error trying to query a database.

```
URL original: drachenlochmuseum-v%25c3%25a4ttis.html
URL decoded: drachenlochmuseum-v%c3%a4ttis.html
URL decoded 2nd time: drachenlochmuseum-vättis.html
```

The decoded URL is used in the database query and that fails because the database driver would like to replace wildcards `%c` with parameters that were not provided.

Stack trace:

```
Exception: Too few arguments to build the query string
#27 vendor/contao/core-bundle/src/Resources/contao/library/Contao/Database/Statement.php(304): replaceWildcards
#26 vendor/contao/core-bundle/src/Resources/contao/library/Contao/Database/Statement.php(249): execute
#25 vendor/contao/core-bundle/src/Resources/contao/library/Contao/Model.php(1102): find
#24 vendor/contao/core-bundle/src/Resources/contao/library/Contao/Model.php(973): findBy
#23 vendor/contao/core-bundle/src/Framework/Adapter.php(38): __call
#22 vendor/contao/core-bundle/src/Routing/RouteProvider.php(493): findPages
#21 vendor/contao/core-bundle/src/Routing/RouteProvider.php(88): getRouteCollectionForRequest
#20 vendor/contao/core-bundle/src/Routing/LegacyRouteProvider.php(43): getRouteCollectionForRequest
#19 vendor/symfony-cmf/routing/src/NestedMatcher/NestedMatcher.php(141): matchRequest
#18 vendor/contao/core-bundle/src/Routing/Matcher/LegacyMatcher.php(69): matchRequest
#17 vendor/symfony-cmf/routing/src/DynamicRouter.php(271): matchRequest
#16 vendor/symfony-cmf/routing/src/ChainRouter.php(188): doMatch
#15 vendor/symfony-cmf/routing/src/ChainRouter.php(158): matchRequest
#14 vendor/symfony/http-kernel/EventListener/RouterListener.php(115): onKernelRequest
#13 vendor/symfony/event-dispatcher/EventDispatcher.php(212): doDispatch
#12 vendor/symfony/event-dispatcher/EventDispatcher.php(44): dispatch
#11 vendor/symfony/http-kernel/HttpKernel.php(126): handleRaw
#10 vendor/symfony/http-kernel/HttpKernel.php(67): handle
#9 vendor/symfony/http-kernel/Kernel.php(198): handle
#8 vendor/symfony/http-kernel/HttpCache/SubRequestHandler.php(85): handle
#7 vendor/symfony/http-kernel/HttpCache/HttpCache.php(448): forward
#6 vendor/symfony/framework-bundle/HttpCache/HttpCache.php(57): forward
#5 vendor/symfony/http-kernel/HttpCache/HttpCache.php(420): fetch
#4 vendor/contao/manager-bundle/src/HttpKernel/ContaoCache.php(46): fetch
#3 vendor/symfony/http-kernel/HttpCache/HttpCache.php(317): lookup
#2 vendor/symfony/http-kernel/HttpCache/HttpCache.php(192): handle
#1 vendor/friendsofsymfony/http-cache/src/SymfonyCache/EventDispatchingHttpCache.php(98): handle
#0 web/app.php(58): null
```

Commits
-------

8ae25820 Fix a potential error if the URL has percentage in it
8caaf252 Fix unit tests
509f7624 Correctly encode the page aliases

Description
-----------

We encountered an `ErrorException` when the page of external redirect type has an insert tag that returns an empty string.

The problem in fact happens in the `UrlHelper` component of Symfony, but I think we should fix it on our side nevertheless.

Stack trace:

```
ErrorException: Warning: Uninitialized string offset 0
#36 /vendor/symfony/http-foundation/UrlHelper.php(42): Symfony\Component\HttpFoundation\UrlHelper::getAbsoluteUrl
#35 /vendor/contao/core-bundle/src/Routing/Content/StringResolver.php(40): Contao\CoreBundle\Routing\Content\StringResolver::resolve
#34 /vendor/contao/core-bundle/src/Routing/ContentUrlGenerator.php(150): Contao\CoreBundle\Routing\ContentUrlGenerator::resolveContent
#33 /vendor/contao/core-bundle/src/Routing/ContentUrlGenerator.php(161): Contao\CoreBundle\Routing\ContentUrlGenerator::resolveContent
#32 /vendor/contao/core-bundle/src/Routing/ContentUrlGenerator.php(70): Contao\CoreBundle\Routing\ContentUrlGenerator::generate
#31 /vendor/contao/core-bundle/contao/modules/Module.php(349): Contao\Module::renderNavigation
#30 /vendor/contao/core-bundle/contao/modules/Module.php(326): Contao\Module::renderNavigation
#29 /vendor/contao/core-bundle/contao/modules/Module.php(326): Contao\Module::renderNavigation
#28 /vendor/contao/core-bundle/contao/modules/ModuleNavigation.php(82): Contao\ModuleNavigation::compile
#27 /vendor/contao/core-bundle/contao/modules/Module.php(213): Contao\Module::generate
#26 /vendor/contao/core-bundle/contao/modules/ModuleNavigation.php(45): Contao\ModuleNavigation::generate
#25 /vendor/contao/core-bundle/contao/library/Contao/Controller.php(410): Contao\Controller::getFrontendModule
…
#1 /vendor/friendsofsymfony/http-cache/src/SymfonyCache/EventDispatchingHttpCache.php(96): Contao\ManagerBundle\HttpKernel\ContaoCache::handle
#0 /public/index.php(42): null
```

Commits
-------

756336e7 Fix a potential issue if the insert tags return an empty string in th…
0a9330c2 Throw an exception if the insert tag returns an empty value
46de08ef CS + Unit test
89521539 Rename the test method