Add our 'proposal' for lessons on the carpentries incubator repo

[Erioldoesdesign]

https://github.com/carpentries-incubator

They have a proposal process when adding a new issue to https://github.com/carpentries-incubator/proposals/?tab=readme-ov-file

I'm currently progressing through this as a 'placeholder'

• Create draft content to be linked in the proposal issue in the incubator repo here in this strudel curriculum repo.
• Document what was added via the proposal template here in this strudel curriculum repo.
• check over lesson templates https://carpentries.github.io/lesson-example/ and https://github.com/carpentries/workbench-template-md?tab=readme-ov-file