Description and Category improvments

[Nexela]

If a mod has a 'readme.md' file in the root and the description in the portal edit box is blank it should use the readme as the description.

Category could be read from the info.json as a string (or array depending on how it is set up), And if the category string doesn't match a valid category (typos/ect) it should display 'no category
'category' : 'Cheats'