feat: Add initial support for Unreal Marketplace.

[Kjell291]

Added initial support for the unreal engine marketplace as requested in #257.
There still is much room for improvement, but it's working.
To install a package one should select the project folder located in ~/Documents/Unreal Projects.

Fixes #257.

[flavioislima]

Good work, man! I think this feature will be really useful for devs in general and I received this request since Heroic's first release but I had no idea on how to implement it!

codewise looks good, I just think that we might add another menu or switch for the market place since it is something specific for game devs.

I was thinking that we can have a submenu under Library with a link to show only the items under market place. What do you think? We can discuss that and ask for other devs review on our discord development channel.

[SaladinAyyub]

Thanks for this ! The thing that is missing.

We can download assets to the project however Marketplace also has whole project samples which simply gets installed in "Unreal Projects" directory. like this one (https://www.unrealengine.com/marketplace/en-US/product/cesium-samples
) for this EGS requires Unreal Engine to be detected as it sets up the whole project. We can have option in Heroic to choose engine directory as people install it in different paths. Or just install the sample project and user has to setup and build it themselves which is fine anyway.

[adityaruplaha]

This will cause severe conflicts with the Electron refactor as this entire module is being overhauled. So I strongly advise against merging this right now.
Also the OOP approach should clean up this code further.

So please, hold your merge for a week or two. I'll try to review it in a few hours.

If after the refactor the code looks too complex to add this (which it shouldn't really), I'll do it myself, and add @Kjell291 as co-author. Sounds good? Sorry about stalling development.

[Kjell291]

Thanks for all the feedback.
I will continue working on this.

codewise looks good, I just think that we might add another menu or switch for the market place since it is something specific for game devs.

I was thinking that we can have a submenu under Library with a link to show only the items under market place. What do you think? We can discuss that and ask for other devs review on our discord development channel.

Another menu would be a good idea with the option to filter for specific Engine versions.

[ianwijma]

No complains from my end beside the points already made

[adityaruplaha]

LGTM. If the tests go fine, I'll merge this.