[cache:context:debug] Create command and move cache:rebuild command

[smalot]

Create cache:context:list command and move cache:rebuild command into new namespace.

[smalot]

This new command list all available contexts which can be used in cache config:
https://www.drupal.org/developing/api/8/cache/contexts

Useful if context are added via multiple contrib modules

[enzolutions]

Awesome contribution @smalot , only a small change, please rename the class and debug as cache:context:debug to maintain consistency with others commands

[smalot]

Ok for me, with great pleasure !

[jmolivas]

@smalot Do you mind to:

1. Rename commands classes

src/Command/Cache/CacheRebuildCommand.php
as
src/Command/Cache/Cache/RebuildCommand.php

src/Command/Cache/CacheContextListCommand.php
as
src/Command/Cache/ContextDebugCommand.php

2. Update config/services/cache.yml file to reflect namespace changes.

3. Update command classes

use Symfony\Component\Console\Command\Command as BaseCommand;
and
class CacheContextListCommand extends BaseCommand

with

use Symfony\Component\Console\Command\Command;
and
class CacheContextListCommand extends Command

[enzolutions]

Works like a charm, thanks @smalot

[smalot]

My pleasure !

[jmolivas]

@smalot great work, thanks for the PR and the super-fast reply.