Update tracks, migrate dev to main

[veidenberg]

Description

This PR:

• Migrates from dev to main branch (to remove dev branch)
• Updates ci to migrate from dev to main branch
• Brings all beta 3 track data updates to main branch for reloading the tracks database
  • redistribution of track order values (this commit; visible track order not changed)
  • will go together with already merged changes (this and this) to update tracks DB
• Updates documentation

Related JIRA Issue(s)

ENSWBSITES-2840

Review App URL(s)

Tracks have been reloaded from this branch to dev: http://dev-2020.enseml.org

Knowledge Base

NA

Example(s)

Track payloads from Track API should have the metadata values (e.g. labels/descriptions) included in this PR (templates/csv files).

Related tasks

After this PR is merged:

• Reload tracks to staging/prod (SOP) after tracks look good in dev
• Remove dev branch after the new ci/cd pipeline is confirmed working

Checklist

• Black formatting
• Tests