Added descriptions for libraries settings.

[LiborBatek]

Added descriptions for addon's setting for better clarity and fixed small issue in the info text for OIIO category.

Resolves https://github.com/ynput/ayon-third-party/issues/11

Testing notes:

1. Build addon package and upload to the server
2. Check addon's settings categories and added descriptions if correct.

[BigRoy]

I think these are too verbose and not needed descriptions.

To me just "Configure FFMPEG" and "Configure OIIO" could suffice - but the label of the section already clarifies what it's about. I'm not too bothered with adding it - but it does feel more cluttered to me.

[LiborBatek]

I have just started to add those descriptions going addon by addon (from top to bottom) as I like the tips really.

I get your point but the more info the better imho. Maybe its clear to you what fffmpeg is for and OIIO but it actually helped me to understand those a bit more (by searching for the definition online)...now it makes it more clear to me personally.

...speaking of cluttering the UI its more a matter of how its shown then the actual wording I have also seen much longer and clipped descriptions accross AYON and settings....

I have to admit, I would like to have those always as hoover over tips much more than these header ones tho. But thats something out of my capabalities...

@m-u-r-p-h-y any opinion on this?

[iLLiCiTiT]

(There are no changes in the PR)