[EPIC] Plugin Architecture

[phanimahesh]

A lot of changes need to be done to properly support plugins:

Capabilities of plugins:

• Defining the following strategies: auth, rate limit, load balancing, logging/analytics
• Define and manage their own private data without having to bring their own storage layers
  Example:
  Key based auth should be able to store keys in mnesia (or whatever other core data stores we support later) without having to deal with mnesia directly.
• Define their own HTTP routes under admin API
  Example:
  Key based auth plugin needs routes to generate and revoke keys
• Can be enabled or disabled on the fly
  Adding new plugins or disabling existing ones should not require recompiling the project
  It should be possible to enable/disable plugins in a running instance without rebooting

This epic tracks all work related to these efforts.

All of these require that a plugin registration and initialisation process be established, along with well defined apis for plugins.