feat(webviewer): Create admin privilege level to protect config and logs

[hickey]

What this changes

This change adds an admin flag to the session data to enable general viewing of bot information by any unauthenticated user and restrict the configuration and logs to users that have authenticated using the web_viewer_password setup in the configuration file. In addition, several actions (delete, favorite and geocode location) on the contacts page have been disabled when the user has not authenticated. Users now authenticate using a login button at the top of the page.

Why

There is a good amount of information that the average user can find of interest that MeshCore Bot collects. In addition, this information helps educate the users about the MeshCore network and some of its inner workings.

Testing

Tests have been included. Live at https://dab-bot.wt0f.com/

Checklist

• Branched from dev and targeting dev
• make test passes
• make lint passes (ruff + mypy)
• Frontend lint passes if templates changed (npm run lint:frontend)
• Tests added or updated for behavior changes
• CHANGELOG.md updated under ## [Unreleased] if user-visible
• Config changes are reflected in config.ini.example (and the minimal/quickstart
  templates where relevant) — CI validates these with validate_config.py --strict
• New docs pages are added to nav: in mkdocs.yml
• Any new command justifies its airtime and defaults conservatively

[hickey]

While I am thinking about it, here are some screen shots of the page header to understand how this change is implemented.

Here is the contacts when viewed as a non-admin: