Fix Tags

[Mythicaeda]

Tags are gone from activity_directive. They should be available as an array still in the activity_directive_extended view
There is a tags table now, as well as join tables with plan, activity directive, and some scheduling/sequencing tables.

[cartermak]

De-scoping from v2 as I've removed tags support for now, but keeping the issue open for reconsideration in the future.

[cartermak]

Addressed by #108 , #117 , and #119