OPENDJ-1602 (CR-5566) New pluggable storage based backend

Reduced the number of compilation errors in package "org.opends.server.backends.pluggable".



PersistItStorage.java: ADDED
Initial implementation of the Persisit storage

JebException.java: REMOVED - replaced by StorageRuntimeException for now.

DatabaseEnvironmentMonitor.java: ADDED
Copied from org.opends.server.monitors.DatabaseEnvironmentMonitor and stripped out all JE related code + changed client code to use it.

SuffixContainer.java, jeb.EntryContainer.java:
Removed getEntryCount() from interface because I need to add a ReadableStorage parameter which is unacceptable for this class.



pluggable.EntryContainer.java:
Worked with TreeName objects instead of plain String objects.
Replaced all former JE calls of "if (environment.getConfig().getTransactional())" by using a straight (Read|Write)Storage object which implementation may or may not be transactional.
Removed preparePrefix().

EntryIDSetSorter.java:
Used EntryContainer instead of SuffixContainer.

RootContainer.java:
Removed now useless methods + code.



*.java:
Passed (Readable|Writable)Storage parameters down method calls.
Replaced all references to JebException by StorageRuntimeException.
In several applyConfiguration*() methods, created write operations.
In applyConfiguration*() methods, created a ConfigChangeResult object at the start of the method and accumulated information on it instead of creating it at the end of the method + passed the ConfigChangeResult object down method calls.