Add project display names

[NonSwag]

Is your feature request related to a problem?

Two projects cannot have the same name, therefor if you have a plugin that is called like another you have to change yours which is annoying if the project is already established under this name

Describe the solution you'd like.

The possibility to either define a custom name that is displayed when viewing the project
Also, the display name should be used in searches instead of the slug
For compatibility, I would suggest displaying the slug if no display name is defined
By that, display names can be optional

Describe alternatives you've considered.

Changing the project name

Other

Modrinth has the same feature, and it works like a charm

[MiniDigger]

Not having display names was an explicit choice we made, since we didn't wanna have people the stupid situation spigot has where the display name is full of ads or other dum stuff

I guess we could have a display name that has the same strict rules as the current name tho, idk how I feel about that yet.

[NonSwag]

Good point, imo the same restrictions from the slug should apply