Added a New Card Filter For Labels

[nkuleedube]

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[mostertb]

Hi @peace-d

Thank you for taking the time to submit this feature! We really do appreciate it.
My apologies on the delay in getting you feedback

I will be giving comments inline as well as on the your comment on the related issue but here is some general feedback:

Firstly, in terms of the feature that is discussed in #2, we are looking specifically to filter to cards that have at least one label that has a chosen name. Consider the following:

As you can see, Trello has allowed by to define two different labels with the name 'Alpha'. In this case, as a user I should only see 'Alpha` once as an option when setting up the filter and the filter should then include cards with either the Orange or the Yellow label in the above example.

Your code filters to cards that have a specific label (via filtering on the ID field). While not being explicitly what is described in #2, this is a useful too! Im happy with you to either change this PR to be in line with #2 or to change the display (and class name) to make it clearer that the filter provides the new functionality of filtering to a specific label. Let us know which you prefer.

Secondly, please could I ask that you run your code on a test board. One of the other recent PRs has resulted in the composer install needing a little more memory. If you're running into this issue, have a look at the (Memory Limit Errors)[https://getcomposer.org/doc/articles/troubleshooting.md#memory-limit-errors] section of the composer docs.

This PR is showing a lot of promise. I look forward to seeing your next push

[mostertb]

The display for the setup renders as follows:

Configure Filter: Has Label
Select Label to filter by:
  [0] 1 Alpha
  [1] 3 Alpha
  [2] 4 Bravo
  [3] <- Back
 >

You can rely on the ChoiceQuestion to do the option numbering for you

[mostertb]

If you choose to go implement the functionality in #2, then this should probably change to something like Label Name to differentiate it from the alternate functionality of matching a specific Label.

See \AppBundle\Helper\CardFilter\LabelColourCardFilter for reference

[mostertb]

If you chose to go implement matching a specific label, then have a look at how the labels are rendered in \AppBundle\Command\CardFilterCommand::printFilteredCards()

This covers Labels without names and attempts to differentiate Labels by colour