Unify the naming convention of names in this repoistory

[ericwindmill]

For every sample:

• The name should reflect the ingredients. For example, compass_app becomes architecture_mvvm
• The name in the pubspect.yaml should reflect the directory name (required for Add 'Open in Firebase studio' button to samples' readmes wherever possible #2498)

[domesticmouse]

Be wary of changing the path of samples, you will break links. That's why migrated experimental app directories still exist, with a README pointing to the new location.