Also run Salsa CI to ensure package pass Lintian and other Debian QA

The Go team pipeline test-archive.yml builds and runs tests on the Go package purely using Go tooling.

To test if the build will pass in Debian and not fail on e.g. missing build depends, and to verify that Lintian passes, autopkgtest (if any) passes and so forth allow users to run Salsa CI. More about Salsa CI in the README at https://salsa.debian.org/salsa-ci-team/pipeline.

Initially enable Salsa CI only when triggered manually.

It can later be made automatic if deemed that there is good CI runner capacity, and if salsa.debian.org instance runners are enabled for the go-team by default.

Testing in go-team

This can be seen in action at in a go-team project at https://salsa.debian.org/go-team/packages/golang-golang-x-text/-/pipelines/768406

Initial run:

After pressing "Play":

This is stuck as the salsa.debian.org instance runners are not available in the project. Enabling them is independent of this MR and requires Go team project admin access.

Testing in fork

The same commit can be seen in action on a generic fork at https://salsa.debian.org/otto/golang-golang-x-text/-/pipelines/768404

Initial run:

After enabling instance runners and pressing "Play":

Renaming gitlab-ci.yml to salsa-ci.yml it out of scope for this MR, but should be done later.