demo_umami_tour should not be a separate module

Problem/Motivation

The demo_umami_tour module is a separate, profile-specific module inside of the demo_umami profile even though it's sole purpose is to provide configuration, which can be done by the profile itself.

In #2989541-5: Add a welcome tour to Umami @kjay says:

Whilst we're developing the feature, @smaz believes it will be easier to keep the tour as a module since you can enable/disable the module with Drush each time the tips are edited or new ones added.

But the adding of the new module was never rectified in the further development of that patch and now the module lives in Drupal core.

This causes unnecessary maintenance overhead.

Concretely, in #3059545: Improve \Drupal\KernelTests\Config\DefaultConfigTest to install all optional configuration it was found that because the tour configuration is in a separate module it is not covered by DemoUmamiProfileTest::testConfig().

Proposed resolution

Remove the module and move the configuration it provides into the profile itself. Nothing will change funtionally, the Umami tour will still be there.