add templates directory as volume in docker compose file

[sharkfin009]

Scope

What's changed:

just one line in the docs: added templates as a volume in the docker compose in the self-hosting guide

Potential Risks / Drawbacks

N/A

Review Notes / Questions

N/A

[paescuj]

Thanks for your contribution!

We require the CLA to be signed before we can accept this pull request.
To do so, could you add the email address used for this commit to your GitHub account so that it can be associated, and then add your GitHub username to the end of the contributors.yml file, if you accept the agreement?

Please note that some unrelated changes were included in this pull request, which I've dropped. It didn't seem too sensitive to me, but if you think it is, please request a full deletion via GitHub support: https://support.github.com/request/remove-data

[sharkfin009]

thanks @paescuj , done ;) I will try and go through the docs and do another PR for all mentions of the templates folder

[pwnkdigital]

The guide needs updating as well, specifically the Add Template To Directus section.