Forms progress

[Vinai]

This issue is my high level todo list while implementing forms support. For details on what is planned check #27. For details on the current state have a look at the hyva-forms branch.

• [x] Create basic types and templates (97ad1ed)
• [x] Form config XML converter (5b52aadcd674113b95bd6e5c4160d8e94ffcdf6e)
• [x] Test forms XML merging with ID attributes (ab2257b2809c76e1259b30c973c6dbfd555ed858)
• [x] Create field declarations from field config (e272676)
• [x] Form entity type determination (e5d0836)
• [x] Entity loading (9a97b08)
• [x] Extract groups from config (and entity/entity type if EAV) (e63c591)
• [x] Extract fields from entity (e63c591)
• [x] Merge form field declarations from entity with declarations from config (56eafb0)
• [x] Render sections and groups
• [x] Render fields by type
• [x] Create hyva-forms.xsd (and add to config reader)
• [ ] Entity saving
• [ ] Render buttons
• [ ] Add JavaScript support for buttons, fields and form submission (see #35)

[Vinai]

Every essential part has been implemented. Currently a lot of manual testing is happening.