cdoc2-key-shares-openapi-1.0.1-draft

Merge branch 'RM-4211_key-shares-updates' into 'master'

* add `x-cdoc2-auth-x5c` header parameter.
* Remove 'format: byte' for `nonce` and `x-auth-ticket`
* rename X-Auth-Ticket -\> x-cdoc2-auth-ticket to follow conventions in OAS spec

See merge request cdoc2/cdoc2-openapi!5