Remove Last Modified columns from file listing.

Need more space for a file upload time column. Users would like the
ability to sort files by date uploaded.

It turns out that the only SQL statement in this building block had to
do with retriving the Last Modified By and Last Modified Date columns.
Since the SQL statement was slow, it was better removed anyways.
Update alerts database when metadata updated.

Unfortunately, this breaks the generalized nature of the building block
since this is a UBC specific feature. We want to notify the copyright
alerts building block when a file's copyright has been updated.
Copyright alerts indexes files that doesn't have a copyright metadata
tag, so when people update copyright in the metadata building block, the
change should be reflected instantly.

This is done by passing a list of the files updated to a copyright
alerts building block rest API call which will delete the files from its
index. The rest API call is performed by a Spring client.