Initial package setup; configuration & dependencies for CAS authentication

[rlskoeser]

I used hatchling to initialize a new project with a pyproject.toml file, and I switched to Apache 2 which is our default license.

• includes a pre-release version of django-pucas as a python dependency, for easy Princeton CAS authentication setup
• settings file that augments/overrides the eScriptorium settings and can be included in local settings file
• urls file that augments/overrides the eScriptorium urls to add the urls needed for CAS authentication
• templates directory with a login template to override the default eScriptorium login to include the Princeton CAS authentication partial template
• preliminary readme with setup instructions and documentation about what changes the htr2hpc settings make

Changes related to #10

[cmroughan]

README looks good, installation and explanation of the adjusted settings make sense to an outside perspective 👍

login.html also looks good. In the future we would discuss whether there would be any need for a login with a local site account at all -- I see that option is built into the pucas template itself, and it works just fine for now (especially with the dummy accounts being used for testing).

Otherwise the license thing was the only adjustment I noticed when looking over things!