Isovector/brig servant 2022

[battermann]

Part of SQCORE-1166. Ports the Brig UserHandle API to use Servant.

Leaving the last two checkboxes unchecked because I don't know the answer to them.

Checklist

• The PR Title explains the impact of the change.
• The PR description provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
• changelog.d contains the following bits of information (details):
  • A file with the changelog entry in one or more suitable sub-sections. The sub-sections are marked by directories inside changelog.d.

[mdimjasevic]

@isovector , we've been experiencing issues with the CI, which then prevents this PR (and all the other PRs) from getting a green light. We'll retrigger the build in CI as soon as the issues are resolved.

[isovector]

CI is green --- someone mind reviewing it? @elland @battermann @mdimjasevic thanks!

[mdimjasevic]

CI is green --- someone mind reviewing it? @elland @battermann @mdimjasevic thanks!

I see that two endpoints listed in https://wearezeta.atlassian.net/browse/SQSERVICES-1642 are not covered by this PR:

• GET /users/:uid/rich-info
• GET /teams/:tid/search

Should they be part of the PR or should they come in a follow-up PR?

[isovector]

@mdimjasevic I'm happy to merge this as is and follow up in a second PR.

[mdimjasevic]

Looks good!