[proposal] Add relay-forms in relay-hooks

[morrys]

The idea is to integrate my relay-forms library into relay-hooks which allows:

• dynamic management of form fields
• a super performing rendering, taking advantage of all the benefits of relay
• Small bundle compared to current libraries to manage forms

Documentation: relay-forms

Things to do:

• import relay-forms sources into "src / forms"
• update the documentation
• integrate tests
• integrate sample projects

[morrys]

A few days ago I decided to manage hooks for forms externally

• react-relay-forms: it has the official react-relay dependency
• relay-forms: depends on relay-hooks, my OSS version of relay hooks
• relay-forms-nodeps: it has no dependencies, I only brought the relay functions needed to manage the store into the library, doing a careful cleaning to optimize the bundle size

I proceed to close the issue