[Feature] support disabling SSL verification

[TreeN0de]

Hey,

I need to disable the SSL verification. Therefore I want to use the option of the lib requests.Session. Just passing the option to verify SSL to the request Session.

[lociii]

Wouldn't it make more sense to make the whole session injectable?
This would also solve the issue that there is no way to properly set timeouts for the requests to Zammad.

See #249

[joeirimpan]

#206 (comment)
Isn't it easier to change the session attribute directly?

[lociii]

That would require to copy the initialization of the session (like setting headers, etc.) from the init.