fix(#zimic): file support improvements

[diego-aquino]

Fixes

• [#zimic] Extended support to use binary files as response to intercepted requests. Previously, the serialization algorithm for RPCs between remote interceptors and interceptor servers could transfer binary content incorrectly.
• [#zimic] Considered application/xml as plain text content, not blob.

Tests

• [#zimic] Updated the body tests to use random bytes in binary file contents, making sure that the data is processed correctly.

Documentation

• [#zimic] Added a table showing how each content type is automatically parsed by Zimic.
• [#zimic] Added a new section detailing request and response object of intercepted resources.

Closes #206.