make forms pluggable

[fmarco]

Hello,
how about adding this changes ?
I'd like to use custom forms in some projects, what do you think?

[coveralls]

Coverage decreased (-30.1%) to 61.712% when pulling 44fe718 on nephila:feature/pluggable_forms into 173524d on bee-keeper:master.

[coveralls]

Coverage increased (+0.3%) to 92.117% when pulling 460d0e0 on nephila:feature/pluggable_forms into 173524d on bee-keeper:master.

[coveralls]

Coverage increased (+0.2%) to 92.222% when pulling 1b21a4a on nephila:feature/pluggable_forms into 6f912a0 on bee-keeper:master.

[bee-keeper]

Sorry for the late reply @fmarco - could you give me a use case for this scenario? Thanks,

[fmarco]

@bee-keeper Hi, no problem!
A use case could be the following: i'm customizing invitations and i'd like to have a proper control on view forms and admin form to make complex customizations in parallel with invitation model.

[yakky]

@bee-keeper do you have any feedback regarding our use case and implementation?

[maxnordlund]

I also would like to customize the admin forms, so this would be a great addition. However, this PR introduces a lot of unrelated changes and lacks a nice commit message. Would you mind cleaning it up so it can be merged @fmarco?

[fmarco]

@maxnordlund Sure, i'll update this asap!

[maxnordlund]

Thank you

[fmarco]

@maxnordlund done!

[maxnordlund]

Lovely, thanks

[bee-keeper]

Ok thanks for this @fmarco - i did feel it was adding a bit of extra complexity but it's obviously useful to some people.

[maxnordlund]

Would you mind cutting a new release with this @bee-keeper? So we can start using it for real :)