[DOCGEN] Create a Readme file per responders for documentation purpose

[nadouani]

The idea is to automatically produce a better responders documentation.

We will create a script that goes through all the responder folders and generate a readme.md file.

[jeromeleonard]

## Responder's Name

*Description of the responder*

### Responder Flavor's Name (*foreach flavor* )

**Author**: *author* 
**License**: *license*
**Version**: *version* 
**Homepage**: *url*
**Supported TheHive datatypes**: list of *dataTypeList*
**Subscription required**: *true/false*
**Free subscription**: *true/false*
**Registration required**: *true/false*
**Third party service URL**: *service_homepage* 

#### Description

*Description of the flavor*

#### Requirements

*requirements*

#### Configuration

##### *Name* (*foreach configurationItems*)

**Default Value**: *defaultValue*

**Can contain multiple values**: *multi*
**Required**: *required*
**description**: *descripition*