clean up repo

[dosumis]

1. Close stale branches

2. Clean up & better spec parallel pipeline structure:

   • Build branches (ec_individuals & denormalised_markers) differ only in Makefile & dosdp TSVs

3. SOP for branching and merging:

   • Unless changes are to build branch only files, they should be PRs against master & then merged back our to build branches once merged to master.
   • Do not build on Master - only on branches (otherwise git merge master strategy for build branches will not work)
   • Try to limit commits of extra file used in testing on branch/PR.