PROV-923 Fix for bundle-level AC issue in install process

There were a couple of problems here:

1) We didn't validate the bundles before exporting which meant that
bundle access control restrictions for fields that no longer existed or
were no longer valid for a certain table would be exported as well.
That is fixed in the exporter.
2) There was a caching issue in the bundle validation in the Installer.
Since the metadata elements are created just before we add those access
restrictions, they didn't show up everywhere yet. The "give me a list
of all valid bundles" function returned outdated data. I now rewrote
the way we validate bundle names in the installer which should address
this issue and also speed up the "access roles" part of the installer
by a huge amount.
3) Another (unrelated) thing was that it is actually possible that
metadata element type restrictions for table that no longer exist are
still around. I changed the exporter so that this should no longer
happen.