Improve product requirements

A few improvements would be nice for product requirements:

1. Allow specifying exactly what version a product requires

2. Make requirements actually required or optional, calling them “required dependencies” and “optional dependencies” as opposed to “required products”

3. Make different requirements for different product versions (Eg. one store page can have a set of clothing for multiple bases or skins, and you want to require that base’s ownership before that specific version is purchasable)

4. Allow showing what products require your product on that store page, which especially for bases, can be a way to show what products are available for that specific base without having to use search and depend on the search only finding products with that base in its tags or name (eg, clothing sets, for example, can support 10 different bases) and filters for required and optional products that depend on that product

5. Allow making “Optional dependencies” from 3rd party sites, to essentially create links for what you need (shaders, bases off of gumroad/itch, ect) and being able to click that dependency to see what other products also depend on it (helpful for 3rd party bases, like the Novabeast, which is only on Gumroad) and allow the community to associate variants of that link to that one product/provide info on that product. Eg. the Nardoragon now both has a Gumroad and a Booth page, and 2 different products can link one or the other, but Jinxxy needs to see it as an associated product. Probably can make links associate to each-other by a voting system similar to tag voting. Also make a way to have 3rd party products depend on other 3rd party products. This would make Jinxxy the go-to place to use even as a database for off-site products that are community voted!