Add support for Enterprise Team APIs

[Not-Dhananjay-Mishra]

GitHub has several new endpoints for Enterprise Teams that haven’t been implemented yet.

• Enterprise Team
• Enterprise Team Organizations
• Enterprise Team Members

I would like to add support for all of them.

[stevehipwell]

@Not-Dhananjay-Mishra can this be closed now?

[Not-Dhananjay-Mishra]

@Not-Dhananjay-Mishra can this be closed now?

Enterprise Team Organizations and Enterprise Team Members still left, I am currently working on them.

[stevehipwell]

@Not-Dhananjay-Mishra sorry I missed the check boxes in the description.