**What this PR does / why we need it**:

Add the ability to change the Loki `target` argument. E.g. one might
want to use the single-binary which has target `all` but also the
`table-manager` which is not part of it. So one can override the target
with `all,table-manager`.

**Which issue(s) this PR fixes**:
Fixes #7788 

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the `CONTRIBUTING.md` guide
- [x] `CHANGELOG.md` updated