[Proposal] Use unboxed boolean types in ResourceHandlerRequest

There are 2 recent changes that landed in `ResourceHandlerRequest`: https://github.com/aws-cloudformation/cloudformation-cli-java-plugin/commit/ebca1dc12e187b484ed599db65d726a6b23a14c0#diff-adfb207dac8dff5107b68b36280ccad4525f92176184ad2ffff9aa7e591b2e8a and https://github.com/aws-cloudformation/cloudformation-cli-java-plugin/commit/e34f0472d0bc67953f41d4ceb666a175d0a7fb2d#diff-adfb207dac8dff5107b68b36280ccad4525f92176184ad2ffff9aa7e591b2e8a.

Both changes favor boxed Boolean over primitive types.

As a result, the usage of this class implies on importing BooleanUtils or a similar helper in order to avoid constructions like: `if (request.getSnapshotRequested() != null && request.getSnapshotRequested() == true) { ... }`.

And the code that is performing a "naive" boolean comparison like: `if (request.getSnapshotRequested()) { ... }` will fail with a null-pointer exception.

The same stands for the rollback flag.

I wonder if var type boxing was done for some specific reasons? If there are no strict reasons, I would vote for unboxing them to simplify condition checking.