Removes hard-coded infrastructure component host name domain
"svc.local.cluster" during interactive session clean-up procedures,
since this assumption is not really necessary and would not work under
some deployment scenarios, such as on SSL-RIVER.

Closes reanahub/reana-commons#457

Closes reanahub/reana-client#718

Closes reanahub/reana-client#718

When starting a new workflow, publish the workflow to the submission
queue instead of executing the workflow immediately by calling
`set_workflow_status` in workflow-controller.

Closes #690

Pin `setuptools` to the maximum version of 70 to allow working on Ubuntu
20.04 LTS based environments. (New versions of `setuptools` are not
compatible.)

Note that this fix is necessary only for the `maint-0.9` branches and
the REANA 0.9 release series. In `master` we have switched to Ubuntu
24.04 LTS based environments and Python 3.12 and no pinning is necessary
there.

Make sure the secret key is propagated to the Flask app, instead of
incorrectly using the default one.

REANA can now connect to password-protected Redis instances.

The `DEBUG` configuration value is not set programmatically anymore, as
Flask documentation warns that it might behave unexpectedly if set in
code. `DEBUG` can still be customised via the `FLASK_DEBUG` environment
variable.

Allow customisation of the `PROXYFIX_CONFIG` configuration value, to
support deployments where REANA is served behind multiple proxies.

Allow customisation of the `APP_DEFAULT_SECURE_HEADERS_ configuration
value, to be able to configure Flask-Talisman's security mechanisms.

Allow enabling and disabling the `X-User-ID` and `X-User-Session`
headers that were always set on HTTP responses. These are useful only
for debug purposes, and they are not needed otherwise.