Explicit Miniforge license acceptance

[Chroxvi]

This PR makes it more explicit that the user has to accept the Miniforge license terms when using --conda-env with cotainr build as we use Miniforge to bootstrap the conda environment in the container. This PR includes:

• A change to cotainr build --conda-env ... that now extracts the Miniforge license from the installer and asks the user to explicitly answer "yes" to accepting the license terms.
• The introduction of the --accept-licenses option to cotainr build that, when specified, assumes acceptance of all licenses (if any) - to be used in silent background builds where user interaction is not possible.
• An update to the documentation more clearly stating that the user has to accept the Miniforge license terms and has the responsibility of making sure that they have the rights to use the channels/repositories and packages, they specify in their conda environment.
• A refactoring/clean-up around the terminology "conda installer" vs "miniforge installer" to make it more explicit that we use Miniforge.
• A few minor clean-ups related to how CLI options are displayed in help messages.

[Chroxvi]

somewhere the link to the bsd-3 licens are missing. Maybe add a structure if we end up with other packages like mini-forge | bsd-3 | link other-tool | SOME LICENSE | link.

I have added a "Licensing Information" section to the README file and linked it as part of the copyright notice in the documentation footer (see left footer of https://cotainr--40.org.readthedocs.build/en/40/).