Add CardDetail serialization model

[Raudius]

• Target version: master

Summary

Adds CardDetail + BoardSummary models which centralises serialisation of Card database models. This will be useful for the upcoming changes in the overview page (#2807) which will require attaching additional information to the Card (namely: board name) as it will not need to be added in multiple parts of the code.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Documentation (manuals or wiki) has been updated or is not required

[vinicius73]

LGTM;

But, what do you think about renaming Models to Presenters or something similar @Raudius ?
We already have Db folder and we know models aren't directly related to database things.
But it can create some confusion in the future. What do you think?

[juliusknorr]

Nice, good approach I think to move the representation logic out of the actual Db entity layer. I'd be fine with the Model naming as well as its a common term here 👍

[juliusknorr]

@Raudius Mind to squash the commits a bit (especially the different cs fix ones)?

[Raudius]

But, what do you think about renaming Models to Presenters or something similar @Raudius ?
@vinicius73

I copied the idea (and name) from the Collectives app. So I think I will leave it as Model for consistency, at least within the Office apps.