docs: fixes issue of multiple h1 present in python docs

[st-jay]

Summary of problem

• The docs built using pdoc have multiple h1 tags present due to the sidebar having an h1 tag

Summary of change

As per Pdoc's docs on custom templates

• I added the default HTML templates used by pdoc to generate docs in docs-templates directory.
• Updated the make build-docs command to have a --template-dir docs-templates flag so it uses the templates from docs-templates directory.
• Updated the docs-templates/html.mako template to fix multiple h1 issue

- <h1>Index</h1>
+ <h2>Index</h2>

Related issues

• https://github.com/supertokens/for-zenhub/issues/136

Test Plan

• Built the docs using make build-docs
• Compared the built docs to docs currently present on production manually

Screenshots

This Drive folder contains two folders with screenshots - one with the docs currently live on production, and the other with the updated docs.

Documentation changes

No documentation changes required

Checklist for important updates

• Changelog has been updated
• coreDriverInterfaceSupported.json file has been updated (if needed)
  • Along with the associated array in supertokens_python/constants.py
• frontendDriverInterfaceSupported.json file has been updated (if needed)
• Changes to the version if needed
  • In setup.py
  • In supertokens_python/constants.py
• Had installed and ran the pre-commit hook
• Issue this PR against the latest non released version branch.
  • To know which one it is, run find the latest released tag (git tag) in the format vX.Y.Z, and then find the latest branch (git branch --all) whose X.Y is greater than the latest released tag.
  • If no such branch exists, then create one from the latest released branch.
• If have added a new web framework, update the supertokens_python/utils.py file to include that in the FRAMEWORKS variable
• If added a new recipe that has a User type with extra info, then be sure to change the User type in supertokens_python/types.py

Remaining TODOs for this PR

No TODOs remaining

[nkshah2]

@st-jay Formatting of code blocks seems to be different (2.png in the drive link)