[FEAT] Add "Download All Liveries" button

[Manochvarma]

Description

Currently there is no Download All Liveries button in the installer. So, if we need to download the whole package, we need to find the zip file in discord page.

Solution

Why is this the best solution?

Adding this button will allow us to use the installer itself to download the whole package without selecting each liveries separately.

Additional context

None

[davwheat]

Well this shouldn't be difficult so... sure, why not?