Feat: Add locking groups feature

[Laith-Grira]

Change Description

• groups require having a section now
• prof can lock and unlock groups based on the section, a switch button is added in the edit section form
• a label "Locked" is added in the sections table to indicate if a section locked
• students can lock and unlock their groups
• students cannot join a group that has a different section than theirs
• students cannot leave their group if the professor locks all groups
• students cannot unlock their group if the professor locks all groups
• if a student leaves a locked group, the group gets unlocked again
• the group created by a student will have the same section as the student

Related PR/Issues, JIRAs

How to Verify

Verification

• PR/Change is verified in local dev environment

Tests

• Unit tests added/updated
• Integration tests added/updated