Given a resource: get all tags by owner and get owner tags for multiple contexts

[brilyuhns]

This allows to

• Retrieve all the tags to a resource by an owner in one go
• Retrieve owner tags by multiple context in one go

[seuros]

LGTM

@krzysiek1507 @rbritom ^^

[krzysiek1507]

@brilyuhns could you please add specs?

[brilyuhns]

Hey thanks for considering this. I will write some specs soon and update the PR.

[seuros]

@brilyuhns it seem that either your git client or github is not configured correctly.
The commits don't link to your profile.
I can merge, but your profile won't show up in the contributors part.

[brilyuhns]

@seuros I have fixed the author for the commits. Please take a look.

[seuros]

Thank you @brilyuhns

[brilyuhns]

Thanks for the gem :)