ENG-5128: Refactor ElasticHashinator to be able to add multiple tokens at a
time.
Reformat ElasticHashinator.toString() to fit shorter tokens.
ENG-5128: Add ElasticHashinator.equals() for deep equivalence check.
Only load the elastic join coordinator when elastic is enabled in enterprise
edition. Fatal if failed to load it.
ENG-5128: Support moving tokens that don't fall onto bucket boundaries forward.

When adding tokens to the elastic hashinator, if an existing token doesn't fall
onto any bucket boundary and can be moved forward by a new token, the existing
token will be moved forward to the new token's position.
Merge pull request #895 from VoltDB/ENG-5128

ENG-5128: A couple of minor elastic hashinator changes.