[RocksJava] Convenience methods for Options

RocksDB introduced in 3.7.0 convenience methods
for getting ColumnFamilyOptions and DBOptions
instances from predefined configuration structures.

There is now also a method in RocksJava to load DBOptions
as well as ColumnFamilyOptions from a predefined Properties
based configuration.
[RocksJava] Integrated changes in D29025

Addressed review comments.
Merge pull request #405 from fyrz/RocksJava-Convenient-Options

[RocksJava] Convenience methods for Options