package name and python module have inconsistent name

[francoto]

Recent changes update the package name to "rsmetacheck" but the python module remains "metacheck".

I think using the same name for package and Python module is more convenient.

Currently, if I run the package CLI directly I type "rsmetacheck --input " and if I create a wrapper in Python I need to write "from metacheck import cli as metacheck_cli"
I would prefer using "from rsmetacheck import cli as rsmetacheck_cli"

I think this requires changing

• the module folder metacheck to rsmetacheck
• update rsmeatcheck in pyproject.toml (scripts, packages)