Host aggregates missing the metadata column

When the Host Aggregates table was moved to its own panel, we lost the
'metadata' column. Bringing it back. It contains useful information and should
be displayed in the table.

Change-Id: Ic87c31904ead459cbee2283268f8b30ce7d47acf
Closes-Bug: 1289466
Merge "Host aggregates missing the metadata column"