Termpair

- Update dependencies to fix a Python 3.10 incompatibility
- Do not require a specific version of python to run the pex executable
- Add pre-commit and run on all files

- Show user a clear error if the browser is not running in a secure context

- [bugfix] Require command in command line. `termpair` now results in an error instead of displaying no output and returning 0.
- Upgrade JavaScript dependencies

- [feature] add small, dark grey outline around the terminal
- [bugfix] center the terminal instead of left aligning it
- [bugfix] better text spacing in bottom status bar

- [feature] Store user input values of the terminal id, key, and host, and restore them when the page loads
- [bugfix] Ensure width fits on mobile devies

**Breaking API Changes**
In this version, TermPair clients from previous versions cannot connect to this TermPair server

- Use new key sharing scheme: Different keys used in different directions; keys rotated
- [bugfix] Terminal dimensions in browser match upon initial connection, instead of after resizing
- Allow static site to route terminal traffic through other server. If static site is detected, user can enter the terminal id and server url in the browser UI.
- Allow Terminal ID and initial encryption key to be entered on landing page
- Add additional random string to each encrypted message
- Display version in webpage
- Add troubleshooting instructions to webpage
- Rename `--no-browser-control` argument of `termpair share` to `--read-only`