Integration and validation of the Bastion service to manage service tokens in the agents

**Impact of the new feature**
WMAgent

**Is your feature request related to a problem? Please describe.**
We need to integrate the work done in #12144 and #12199 with the Bastion service.

**Describe the solution you'd like**
To be investigated

**Describe alternatives you've considered**
None for now

**Additional context**
Token transition

FYI @amaltaro @khurtado @stlammel 