Refactored server.js to move out parsoid-rt specific code.

* Moved out performance stats into its own file.
* Moved out selser and flagged regressions stuff into its own file.
* These two can be enabled or disabled independently.
* Added support for "application/json" post of results from clients.
* Fixed a syntax error in the create_everything.mysql file
* Localhost and Remote title/result servers can be set up separately,
  alongwith url generation for those results.
* With all these changes, the RT server can be more easily used for
  visual diff testing.
  - Verified working with visual diff client.js locally.
  - Will push that to github repo separately.

Change-Id: I2b01c7f0589f35b981d8b996c9ac4a0834023cc5
Merge "Refactored server.js to move out parsoid-rt specific code."