Add user visible description field to recipe revisions

[mythmon]

Recipe revisions should include a description field. This should be an optional field, and won't be included in the minimal recipe serializer used in /api/v1/recipe/signed/.

This is different from #1082 (a general notes field) in that it is outward facing. It should be suitable to be seen in Firefox and as a description on dashboard for a recipe. The notes field would be for users of the Normandy admin itself, and although not private, its audience is users of the Normandy system itself.

[anubhavsinha98]

Hey can I work on this issue?

[mythmon]

Hi @anubhavsinha98. Thanks for the interest. Feel free to work on this issue. However, Normandy is a sort of challenging project for external contributors. It might be worth joining us in #normandy on irc.mozilla.org before you get started.

[anubhavsinha98]

Thanks @mythmon for mentioning ! Well I am a very much new to open source and just started contributing so can you just help me out in clearing this issue !

[shell1]

since this was filed - we have built this in a different way. modern preference and add-on studies have this idea included. will grow out old type of experiments. will need to add to any new type of content and current solution not backwards compatible (older clients).

we could build it more ideal, generic way (so left as P5) - but today it is a property of specific actions to have user facing description. not all actions have this. it's an action argument instead of property of recipe revision.

Slug is likely the bigger impact. slug in API, exposed in name in delivery console, distinct from other name...