Improve latency when reading small objects.

• Make Prometheus Histogram Buckets configurable.
• Set NONAGLE on TCP Socket.
• Increase message size in GRPC client for the Metadata Server.
• Add logging before throwing a std::runtime_error.
• LocalFile: Asynchronously update file length.
• LocalFile/MMAPFile: Support notifyUnused
• MMAPFile: unmap file when the file is no longer in use.
• Integrate CMake Compiler option for Profiling
• Various: Cleanup formatting.