Pytest-plone

New features:

- Add fixture `generate_mo` to compile translation files during tests [ericof] 5
- Move from `gocept.pytestlayer` to `zope.pytestlayer` [ericof] 11


Internal:

- Implement plone/meta [ericof] 6
- Clean up dependencies for pytest-plone [thet], [gforcada], [ericof] 9
- Pin pytest version to be lower than 8.0 [ericof] 12
- Update plone/meta [ericof] 13

- Add `app` fixture.
[ericof]

- Add `setup_tool` and `profile_last_version` fixtures.
[ericof]

- Add `get_fti` and `get_behaviors` fixtures.
[ericof]

- Add `get_vocabulary` fixture.
[ericof]

- Fixtures `portal`, `http_request`, `installer`, `browser_layers`, `controlpanel_actions`
[ericof]

- Initial release
[ericof]