[FIX] Batch fixes and improvements

[dolfinus]

• Fixed requests errors:

• • using extract_arguments for GET /api/model/:id request with no body
• • returning werkzeug.exceptions.BadRequest whle passing body for GET requests
• • datetime.datetime is not JSON serializable while GET date fields
• • Removed magic of parsing domain value for GET /api/model

• Fixed using application/www-form-urlencoded instead of application/json for request data

• Return record data instead on non-JSON messages for PUT and PATCH requests

• Return no data for DELETE request

• Id and model name checks are wrappers now instead of copy-paste

• Using exact routes for each method

• Updated documentation for methods usage

[dolfinus]

This pull request also fixes issue with Access Token request.

[ajepe]

There are series of conflict with the existing code base, would have love to merge this. but will find a way around it when am a bit free.