Add postData getter for network request

[rmarot]

This PR is to add a method on the Ferrum::Network::Request object in order to allow the optional POST body to be retrieved (or nil when it does not exist).

It looks like unit tests are skipped for this object, but let me know if this requires additional changes in order to be merged.

[ttilberg]

My small feedback is that this method should be called #body. That would be consistent with HTTP in general, other libraries and be more expected. It’s even in your description of the change ;)

edit: or perhaps, at worst, aliasing it?

[rmarot]

My small feedback is that this method should be called #body. That would be consistent with HTTP in general, other libraries and be more expected. It’s even in your description of the change ;)

edit: or perhaps, at worst, aliasing it?

Yes, honestly I wasn't sure about #post_data, but it looks indeed more relevant to me to use #body.

[ttilberg]

Since the CDP method is postData they both have merit. Curious what the bosses will say.

[route]

Let's alias it as Tim suggested, and I'll merge it

[route]

Thank you

[rmarot]

Thank you

Thanks !