allow for more fine-grained practice opportunities

[kapil1garg]

Practice opportunities are encoded as a venue in whole (e.g, SIG, office hours, Studio), but really it's the practices done in those venues that project objects should be raised in. For example, if a mentor notices that a student would benefit from working on the Approach Tree, the value would be to raise that as a practice opp next time there's LIP (which happens to be on Studio days)