beginnings of a draft glossary

[rossajmcd]

Hi @nickabs @shahidk550. Draft glossary starter for ten (WIP) is up - https://github.com/information-sharing-networks/.github/blob/main/glossary.md ready for your contributions. It's been fun tying myself in knots with atomic and composite definitions - let me know if it is making sense so far. All feedback on structure/formatting for terms is very welcome.

I'm thinking that borrowing the idea of 'related' and adding it when it becomes relevant could be useful.

[rossajmcd]

If you have feedback please do either roll it directly in, create a pull request or create it as an issue here depending on what you would like to do and how much time you have.