Add tooltips to glossary terms

[trickyck]

It would be nice to add tooltips to glossary terms, so that people don't have to navigate away from the page to find a definition.

Resources include:

• https://sphinx-hoverxref.readthedocs.io/en/latest/usage.html#tooltip-on-glossary-terms
• https://myst-parser.readthedocs.io/en/latest/syntax/roles-and-directives.html#roles-an-in-line-extension-point
• https://sphinx-hoverxref.readthedocs.io/en/latest/configuration.html#confval-hoverxref_roles

[matteopilz]

As this issue also addresses the glossary in a similar way as this one, maybe it would be best to close it and rename the other one.