[ENHANCEMENT] Implement API.Static interface

[lorenzobruni]

Create a new API.Static interface to handle static and cacheable content.

[lorenzobruni]

The API.Static interface follows a RESTful implementation but with the difference to allow client-side caching.
This means that an API.Static request can be cached by the caller (i.e. browser) in order to benefit a static implementations.
Example of static implementations are requests of any static outputs such as files (i.e. images, documents etc...) form both the file system and DB.

N.B. Please note this implementation is explicitly used for public records. DO NOT use this interface for requesting sensitive or user-specific data, instead use always the RESTful or JSON-RPC which are never cached on the client-side (i.e. browser)

[lorenzobruni]

Add the following verb to the Web.config in the handlers directive:

<handlers>
  ...
  <add verb="GET,POST" path="api.static" name="API.Static" type="API.Static" />
</handlers>