format WP-properties table prettier
specify status properties
specify basic readable status endpoint
move status to link section of work package
specify 403 for statuses
specify linked WP actions

only specify actions that:
- are linked in the implementation
- link into the api/v3-namespace (nothing outside the API)
- where link targets are already specified

+ also link the edit form that will be specified during this PR
start describing forms
fix aglio warning

[ci skip]
some explanation of field schema

field schema is quite limited as of now, but should suffice for current
needs

[ci skip]
add required attribute to field schema

[ci skip]
fix spelling error

[ci skip]
include an example

[ci skip]
fix more permission typos

[ci skip]
define error responses

includes HTTP 400 for all existing POST/PATCH endpoints

[ci skip]
formatting and stuff

[ci skip]
introduce error indication

[ci skip]
add guarantees about embedded properties

This allows clients to safely skip loading linked resources in case they
are already embedded.
Otherwise they could not safely assume which properties are embedded and
for which they'd need to resolve the link.

It should also simplify the API implementation as there is only
a single representation neccessary.

[ci skip]
remove changeParent action

does not seem to add any value beyond update/updateImmediately

[ci skip]
define payload for invalid/undefined values

[ci skip]
introduce writable attribute