TMSS-1093: export/populate schemas/templates

Closes TMSS-1093

See merge request !611

Resolve TMSS-780

Closes TMSS-780

See merge request !606

TMSS-780: simplified mark_subtask_as_obsolete. no reason to set scheduled_on_sky_stop_time as well which may have unforeseen side-effects

Resolve TMSS-778

Closes TMSS-778

See merge request !610

TMSS-778: made the error_reason field immutable once set, and only settable when state==error at database level wo we catch all cases and not only when using the reast api

TMSS-778: removed remakemigrations script to prevent accidental usage now that we decided to use migrations 001 and 002 as bases and create new migrations using tmss_manage

TMSS-1093: when called from the commandline, don't use parallel uploading to make the log lines sequential/readable