New Rückkanal Events (planning#460)

See merge request !1

we decided to remove it since the status is also removed. so it
wouldn't make any more sense to keep it

since we expand the API to handle replies, we need the reply in the sub
claim. additionally, if we want to move away from using the 'txn' claim
and use the 'sub' claim for cases, it must be possible to specify them
in the sub claim. thats why case:<id> was added.

we either use Zustelldienst or (here), since its a technical specifier
the word "system"

Changed defintions to $def

See merge request !8

Replace $schema enum by $schema pattern

See merge request !5

The $schema attribute defines which schema versions are compatible with this schema. Software systems that validate a SET payload against this schema should not only accept SET payloads which exactly match this schema version but also accept SET payloads that validate against compatible schema versions (same major version)

fix(deps): pin dependencies

See merge request !4

Fix/737 uninline

See merge request !3

Configure Renovate

See merge request !2