This is a variant of 'sendMessage' which creates the queue

Also, improve tests for this.

This contains the postgres dependency, but not haskell.

Polymorphic worker

See merge request !1

Also, worker tests implemented for redis

Otherwise, concurrent calls to 'IF NOT EXISTS' when creating extension
could result in unique constraint errors.

Also, implement TSRepeatNElseArchive handler in worker

Also, fixes to getting conn info from env vars (for tests)

This doesn't compile yet

simple-worker/Main compiles now but doesn't yet work correctly

Doesn't compile yet