[WIP] block types

block types:

__Tasks:__

- [ ] test coverage
- [ ] gather feedback for my changes
- [ ] submit changes to the documentation
- [ ] xml schema
- [ ] cache class rendering
- [ ] blockproperty type changes
- [ ] block content type
- [ ] contentmapper
- [ ] ui in contentbundle

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | yes
| Fixed tickets | none
| Doc           | url to doc