Remove API security annotation

[kevinpapst]

The last release of Kimai core introduced API tokens, which improve response speed of the API from 0.7s/call to 0.2s per call, removing half a second from each API call.

The new tokens including an example are explained at https://www.kimai.org/documentation/rest-api.html

With that change the security annotation became deprecated, it is not needed anymore and can be removed.

This annotation was just used in the API docs, which now ships a global "Bearer token" configuration.

[kevinpapst]

Thanks @KatjaGlassConsulting