Add api-inference docs

[mishig25]

Closes #520

[merveenoyan]

This PR is doing God's work. Thanks @mishig25 🤗 This will make adding docs much easier!
(I rarely add things to api-inference docs and I forget about dev setup every time 😂 for me, it didn't make any sense that it was outside of this repo)

[mishig25]

Closing this issue for now. The detailed parameters page (probably the most important page of the doc) gets auto generated from api-inference. Specifically, all the code snippets (see attached screenshot) are part of python test files, which gets used in generating the doc. Therefore, it is not possible to open-source docs only without open-sourcing the test files.

cc: @michaelbenayoun