SERVER-13681: Remove lock that was an incorrect workaround for Azure Drive write size limitations.

- Limit flushes to 2MB chunks to prevent hitting a limitation in
Azure Network Drives (XDrive) which have a 2MB file write size limitation.
SERVER-13729: Fix Data File Growth on Windows

Reuse an existing lock to use as a lock to handle the race condition
between _flushAll, and the memory mapped file being closed instead
of holding LockMongoFilesxxx for an excessively long time.
SERVER-13792 added runtime and build-time checks for POSIX monotonic clocks. de-inlined Timer::now() implementations
SERVER-14180 fix double free in access planning for $elemMatch
SERVER-11256 improve handling of empty vs nonexistent CollectionMetadata
SERVER-11256 improve handling of empty vs nonexistent CollectionMetadata

Remove long constructor for ChunkVersion
SERVER-11256 improve handling of empty vs nonexistent CollectionMetadata

Rename ChunkVersion::isEquivalentTo to equals
SERVER-14135 Initial skeleton of ReplicationCoordinator interface
SERVER-14135 Use ReplicationCoordinator to determine if replication is enabled
SERVER-12007 add shell helper to create ObjectId from Date