ISAICP-6036: Remove circular dependency - Move Drupal commands outside the repo.

[idimopoulos]

ISAICP-6036

Description

In ISAICP-6037, the changelog command was split off from the repo and now resides in openeuropa/task-runner-changelog - called changelog from now on. As it is normal, since the changelog repo has a dependency towards the task-runner repo since it contains a fraction of the code and is not usable without the later.
However, for BC purposes, and in order to not disturb the workflow of the current projects, a second dependency was added from the task-runner repo towards the changelog repo.
This is causing a major problem for the development. Currently, task-runner requires ^1.0 from changelog and changelog requires dev-master from task-runner.
Before proceeding to the main problem, I think that changing the version dependency in both repos to "*" is not a solution as it might cause issues later in some project.

The main problem is when attempting to develop. While circular dependencies in composer are resolvable, it locks both packages in a specific version. Even if one of the repos has a dependency version of "*" towards the other, the package is still unable to be developed.
The below table will make it clear-er.

changelog ver. req. in task-runner	task-runner ver. req. in changelog	Problem
^1.0 (current)	dev-master (current)	Both repos are unworkable. Let's say I work in task-runner. I create a branch BLAH-001 for my BLAH project. I run composer install. My BLAH-001 requires "changelog": "^1.0" but that repo requires "task-runner": "dev-master" and I just checked out BLAH-001. Composer breaks as there are no candidates to be installed.
^1.0 (current)	*	The same problem as above but only if I am working on changelog. task-runner works fine since changelog does not care about the version
* (current)	dev-master (current)	Same problem as above but for the task-runner repo this time.
*	*	Both repos are workable but compatibility breaks between the packages are not trackable and might break unexpectedly.

The problem becomes heavier with the introduction of our ISAICP-6036 and the #130 which requires Drupal commands to be moved outside and have the same circular dependency. Without "*" in both repos, packages cannot be worked at all as circular dependencies do not allow the creation of new branches.

Change log

• Changed: Drupal commands moved to an external repo.
• Removed: Drupal commands in task-runner.

[claudiu-cristea]

Removal of this file breaks BC as ec-europa/toolkit uses this trait in \EcEuropa\Toolkit\TaskRunner\Commands\InstallCommands

[claudiu-cristea]

...but it should:

• use the \OpenEuropa\TaskRunnerDrupal\Tasks\Drush\loadTasks trait,
• remove the method as now is inherited from \OpenEuropa\TaskRunnerDrupal\Tasks\Drush\loadTasks,
• Add a deprecation error trigger (see Drupal deprecation policies on how to...)

[claudiu-cristea]

Deleting this class, breaks Toolkit's \EcEuropa\Toolkit\TaskRunner\Commands\DrupalCommands.

From #131, bullet 4:

Keep the drupal:settings-setup as default command, so that is guaranteed that Toolkit can override it as it does now but remove the command body and replace it with a call to the openeuropa/task-runner-drupal method.

It seems that this requirement hasn't been honoured. We should keep this command, but deprecate it, triggering the appropriate muted error and adding the deprecation label, as per #131, bullet 5.