Add Support for Wiki

[oemunoz]

Is planned some support for the wiki pages?

https://docs.gitlab.com/ee/api/wikis.html

Tnks!!!

[hanwenbo]

Tnks!!! Add Support for Wiki

[m1guelpf]

Feel free to submit a PR :)

[morinluc0]

Started working on a PR for this request,

I still need to create test cases and functions to perform actions on the wiki from the project class.

[GrahamCampbell]

Implemented. Was available since 9.17.0. :)

[GrahamCampbell]

Thank you @morinluc0. 🚀