[core] Remove old Hadoop configs

Removed HDFS trash info
Tested with trash disabled
[fb] Trash opens up on user current path if possible
HUE-1741 [dbquery] bugs

- PostgreSQL now requires a database name.
  This means that get_databases will return the configured database.
- Moved rdbms libs + db selction part into rdbms app.
- Errors now go away when a new query or explain is ran.
- Revamped front end storage management.
HUE-1501 [oozie] Support coordinator datasets from non HDFS
HUE-518 [beeswax] File Resources support other file systems
HUE-1746 [metastore] Read header from file

Currently the header is not truncated. Will be added separately.
Current tests are good, this is mostly front end.