Merged requested to merge feature/cvfe-unify-assembler into master
Unify the local and subdomain assemblers for CVFE
Unify treatment for fcdiamond on the boundary, treat like other CVFE schemes (non-compatible change)
Add changelog entry for fcdiamond
Remove obsolete local assemblers
depends on !3460 (merged) because it adopts that bugfix to all CVFE schemes.