Added Namespace parameter for InferenceEndpoints, added option for passing model config directly

[shaltielshmid]

1] I added the namespace parameter to the endpoint model config, to allow deploying endpoints from an organization that isn't your private user.

• Added the namespace property to the class
• Added a static method nullable_keys() so that the check for a complete config when creating the endpoint can ignore those.

2] I added the option to specify the model config directly from python code, with a simple check to see if it was given. (Note: I unindented everything after the yaml.safe_load, since after the yaml was loaded there was no need to remain inside the scope of accessing the file).

Sending you sample code to test on slack.

[shaltielshmid]

Great!! I'll add in the docs later tonight or tomorrow.

[shaltielshmid]

Thanks for the comments! Added in the doc strings :)