Test SEAPATH Debian standalone version in CI

[Paullgk]

Is your feature request related to a problem? Please describe.
There are more and more users of SEAPATH that use the standalone version of SEAPATH Debian (without any cluster features).
Currently, this version is not tested in CI, with Ansible deployment. We see recently some regression that break standalone version as it contaminate the latter with cluster features (ex: #689).
This regression hasn't been detected in CI as this version of SEAPATH is not tested (only cluster version).

Describe the solution you'd like
A GitHub action testing the deployment of SEAPATH on a standalone version, in the same way as cluster CI.

[ebail]

Thanks @Paullgk. @insatomcat @eroussy @dupremathieu, that would be great to think about having CI running for Standalone & Cluster mode.

I know that some utilities are considering using SEAPATH in Standalone mode.