IATI Tables docs - move / theme / repo?

[stevieflow]

Currently the link for IATI Tables docs goes to: https://iati-tables.readthedocs.io/en/latest/

We need to have these in the IATI docs theme, plus hosted at https://docs.tables.iatistandard.org/ (if that is our convention for docs sites)

I'm not sure if that then involves hosting these docs in their own repo as per https://github.com/IATI/iati-validator-docs (and others)

Over to @robredpath @tillywoodfield @IsabelBirds

[IsabelBirds]

Noting that exchange rate source needs documenting: https://github.com/codeforIATI/imf-exchangerates