chore: Replace backend with platform

[dmihalcik-virtru]

We have migrated to a new set of backend services and are deprecating the existing python based services. This work in progress replaces the sample web application code and all of the code that brings up a backend and configures some users.

[github-actions]

If these changes look good, signoff on them with:

git pull && git commit --amend --signoff && git push --force-with-lease origin

If they aren't any good, please remove them with:

git pull && git reset --hard HEAD~1 && git push --force-with-lease origin

[github-actions]

If these changes look good, signoff on them with:

git pull && git commit --amend --signoff && git push --force-with-lease origin

If they aren't any good, please remove them with:

git pull && git reset --hard HEAD~1 && git push --force-with-lease origin

[github-actions]

If these changes look good, signoff on them with:

git pull && git commit --amend --signoff && git push --force-with-lease origin

If they aren't any good, please remove them with:

git pull && git reset --hard HEAD~1 && git push --force-with-lease origin

[sonarqubecloud]

Quality Gate failed

Failed conditions
36.1% Coverage on New Code (required ≥ 80%)
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarCloud

Catch issues before they fail your Quality Gate with our IDE extension SonarLint

[dmihalcik-virtru]

Replacing this PR with #282