Make the template project compatible with startproject

[a-musing-moose]

Adds the necessary place holders for ensuring the template project can be used with the Django startproject command.

• Placeholders added to template file (mostly {{ project_name }})
• Really basic usage example in README
• Github action workflow to ensure that the repository is capable of creating a valid project

The Github action workflow startproject performs the following to ensure that we can create a valid project from this repositoiry:

1. Checkout code
2. Install Django. Poetry and Invoke
3. Run the startproject Django command specifying the template directory as the source
4. Poetry install the project created in the previous step
5. Run invoke check on the project - which runs all the static analysis, linting and tests

Closes #19

[jadedarko]

I really appreciate your doing this, Jon

I had wondered if we might want to use cookiecutter for this, but the inbuilt django method is much more straight-forward, especially when there aren't yet any variants

[G-Rath]

note: there's some hardening that we should do at some point, but it's more for consistency than anything serious so I'm happy to leave it as is (and also to do the follow-up PR)

If you're interested, see ackama/rails-template#513 and related for the hardening changes

[a-musing-moose]

I'm not familiar with workflow permissions. I am assuming that since I am never attempting to make any changes to the repo during the workflow run I should be safe to just lock all the steps to read only (with a global no permissions at all)?

If so then I don't see any reason not to include it as part of this PR.

[G-Rath]

yup and we also want to set persist-credentials: false on actions/checkout calls

[G-Rath]

nitpick: I'm thinking that since we're always going to have permissions now, we should have it as the first property for consistency, but it's not super important

Suggested change

	runs-on: ubuntu-latest
	permissions:
	contents: read
	permissions:
	contents: read
	runs-on: ubuntu-latest

[G-Rath]

suggestion: we should explicitly disable persisted credentials since they're not needed for this workflow

Suggested change

	- uses: actions/checkout@v4
	- uses: actions/checkout@v4
	with:
	persist-credentials: false