Implement PowerShell profile

[blakeNaccarato]

My PowerShell profile activates virtual environments detected in the current environment. I could instruct first-time contributors to modify their profile in CONTRIBUTING.md, but it would be nice to ship the appropriate profile options.

Maybe we can include a profile mix-in that can be dot-sourced by users.

[blakeNaccarato]

This issue will now track effort on the PowerShell profile implementation. Things like automatic activation of the virtual environment, populating PYTHONSTARTUP with tooling\.pythonrc.py, and more.

[blakeNaccarato]

Maybe I can minimally touch the user's profile by asking them to run Set-PsEnv if a .env file exists. This keeps the barrier between profile-specific matters and project-specific matters. Then we can ship a .env in the template that touches the relevant environment variables.

[blakeNaccarato]

These two are roughly equivalent:

In the $PROFILE for pwsh:

# If there is an `.env` file in the PWD, load environment variables from it
Set-PsEnv

In .bashrc

#* Import dotenv aka .env environment variables if it is found
if [ -f ./.env ] ; then
    set -o allexport # enable shell option to export all created variables
    source ./.env # now this will export all vars instead of just one
    set +o allexport # disable shell option to export all created variables
fi

[blakeNaccarato]

Even though we aren't bundling a PowerShell profile or .bashrc, the manual first-time setup for a user will need to be documented. For security reasons, this cannot be automated, and instead we will tell the user what to do and why its needed.

[blakeNaccarato]

PowerShell profile tinkering is automatically done in typer w/ shellingham as a way to check which terminal the user has. So maybe it's reasonable to do this, but have a manual "echo text to terminal for you to copy instead" option as well.

[blakeNaccarato]

This is completed in scripts/Initialize-Shell.ps1, which is manually invoked wherever needed to set environment variables and activate the environment.