Create superuser page's stylings

[rajatvijay]

Fixes #3056

Technical details

1. Created a new app_styled_base.html template that loads the component library stylings. It also has some common stylings used across templates.
2. login_base.html & superuser_create.html extend app_styled_base.html

Screenshots

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
• My pull request targets the develop branch of the repository
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

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[kgodey]

Assigning myself to update the copy.

[kgodey]

Pushed a commit with updated copy, unassigned myself. My main objection was "Mathesar account", the concept of having full control over your Mathesar account doesn't make sense. Renamed "account" to "installation".

[silentninja]

I went through the django-related code and it looks good to me!

[pavish]

@rajatvijay

Looks good!

I'd like the file app_styled_base.html to be renamed to something more clearer, something like server_rendered_base.html, as to not confuse with the existing base.html.

I'm approving the PR. Please feel free to rename the file in the same PR or a different one and merge this in.