docs: quickstart instructions for install from PyPI

[joanise]

PR Goal?

On PyPI, like on GH, the quickstart instructions start with checking out EV from GitHub. We should start with PyPI-compatible instructions, then move on to instructions to install from source.

Feedback sought?

Make sure my updated instructions are correct

Priority?

medium

Tests added?

no, but I tested these instructions while writing #600

How to test?

Follow the new instructions and make sure the result is a valid environment.

Confidence?

high

Version change?

no

Related PRs?

no

[semanticdiff-com]

Review changes with  

[github-actions]

CLI load time: 0:00.29
Pull Request HEAD: bff4a6d2b7fe49b296e5a9f4f2b015c628ed2ee9
Imports that take more than 0.1 s:
import time: self [us] | cumulative | imported package
import time:       264 |     110575 |   typer
import time:      6370 |     230585 | everyvoice.cli

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.59%. Comparing base (e3fe86a) to head (bff4a6d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #602   +/-   ##
=======================================
  Coverage   76.59%   76.59%           
=======================================
  Files          46       46           
  Lines        3452     3452           
  Branches      470      470           
=======================================
  Hits         2644     2644           
  Misses        706      706           
  Partials      102      102           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.