ci: add optional submodule bump step

Currently, if there is a need to test submodule integration with
Tarantool and its integration, it is required to create a PR.
That is inconvenient, so this patch introduces the option to run
the same jobs that are triggered by the `full-ci` label as
reusable workflows with the desired submodule revision. This
allows for integration testing of submodules within their
designated repositories.

NO_DOC=CI
NO_TEST=CI
NO_CHANGELOG=CI