Add a Mod Load Order

[megabytesofrem]

We need to support loading mods in a specific, pre-determined order, as this is required when modding games like Fallout or Skyrim.

For example, for a modded installation with two mods (ModA and ModB), ModA should take priority over ModB if specified in a "load-order.json" file.

[
    {
       "mod": "ModA",
       "order": 0,
    },
    {
       "mod": "ModB",
       "order": 1,
    },
]

[megabytesofrem]

This file should also probably have a flag which specifies if the mod requires NVSE/SKSE since mods that depend on NVSE/SKSE require special installation instructions.