This is the first step toward clearing out the redundant metadata from the
coursewareMetadata and getting it from a common source - the courseHomeMetadata.
remove username from coursewareMetadata
Remove courseAccess from coursewareMetadata.
Fix all unit tests
Modify classes that use metadataModel to use courseHomeMetadata for common data.
metadataModel still exists as a mechanism to distinguish if a component is under
courseware or courseHome, and it will be renamed or removed in a later refactor.
3fe5bb1733