[SPIKE] Improve backend documentation (#2177)

* Update code owners to include new folks and remove the departed ones

* Update maintainers to reflect the current personnel

* Update contributing with the latest, and make small changes to readme to make it easier to read

* Update maintainers with Lucas Brown

* Update installation guide to refine instructions and make them easier to follow

* Try emojis to make notes stand out more

* Experiment with note

* Moved installation of data pipeline into a new file (contents TBD), and redid most part of the data pipeline README for clarity and readability

* Add mermaid diagram

* Fix table

* Update readme for clarity and correctness

* Update TOC

* Fix comparator doc

* Add section on internal score comparison

* Move tox information from installation to testing

* Update installation for data pipeline

* Add emojis to make picking out platform-specific instructions easier

* Fix Git caps

* Update for readability

* Add direct link to VS Code instructions

* Fix broken link and improve readability

* Update installation for clarity and proper case

* Update python text

* Clean up information about poetry and poetry lockfiles

* Remove duplicate paragraph

* Fix case

* update date table

* re-adjust table to put links at the end

* Fix a few minor typos

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Co-authored-by: Sam Powers <121890478+sampowers-usds@users.noreply.github.com>

.github/CODEOWNERS

@@ -1 +1 @@
-*       @esfoobar-usds @vim-usds @emma-nechamkin @mattbowen-usds
+*       @vim-usds @travis-newby @sampowers-usds @mattbowen-usds