Using base32 encoding to generate DNS records

The Designate driver generate record names by
hashing and 64-base encoding the instance ID.
The problem is that 64-base encoding can generate
hyphens and upper/lower case letters. Hyphens are
illegal when it is at the beginning of the name.
Name is also case insensitive. So the best solution
is to use BASE-32 encoding.

Change-Id: Ie98a0a50a609207df041c5f0bc2f622701ee9848
Closes-Bug: #1262789
Merge "Using base32 encoding to generate DNS records"