[Summary Issue]: event endpoint, event-kind endpoint

[johannesliem]

(I) Event search endpoint: #155
(II) Honour event: #164
(III) Event-Kind: ('aHR0cDovL3d3dy5jaWRvYy1jcm0ub3JnL2NpZG9jLWNybS9FNF9QZXJpb2Q=',
b'http://www.cidoc-crm.org/cidoc-crm/E4_Period') is used within a related vocabulary (broader)
Period can be found via ID search not via q-search.

So we are not totally sure if the event-kind-search endpoint provides all used event-kinds