add service account bearer token gen

[Omzig]

Summary of the new feature / enhancement

as a consumer that uses a domain service Account, i want to call something like /api/v1/signin/bearer, so that i can use it in other api calls with a bearer TOKEN authen header.

Proposed technical implementation details (optional)

create a new api or return more information in the /signin api that somehow gives me access to the bearer token

i could not find anything that does this in the doc.

Currently the only way i can get the api calls to work is with a cookie login pattern.....