Scan modrinth manifests

If a modpack or zip contains a modrinth manifest, check it for specification of sideness.

Example manifest: modrinth.index.json

Example entries:

{
	"path": "mods/cloth-config-6.2.57-forge.jar",
	"hashes": {
		"sha1": "fe21430bf2daf2ce2b1f6f7e2c01b07ba9d50642",
		"sha512": "2290494e679c1e5bd21fd80148390dfd6101d2e72e8d56ba793f8da236ef878515bec89391a044973ed292cba7a525e6d301c89d75cb216ec8b6e28bae1c7a8d"
	},
	"env": {
		"client": "required",
		"server": "required"
	},
	"downloads": [
		"https://cdn.modrinth.com/data/9s6osm5g/versions/6.2.57+forge/cloth-config-6.2.57-forge.jar"
	],
	"fileSize": 1133103
},
{
	"path": "mods/entityculling-forge-mc1.18-1.5.1.jar",
	"hashes": {
		"sha1": "fbf6368cd26d878ce3d75e899f039a1e51fa49a3",
		"sha512": "ad89d05a41e8b04ca6de0e1b882d779845b1dfdac768e921929f3a567499357518a09f6317305bd01ff6aa6bc40b4d5d5ec91eda2fa648c36506e758ccc74e85"
	},
	"env": {
		"client": "required",
		"server": "unsupported"
	},
	"downloads": [
		"https://cdn.modrinth.com/data/NNAgCjsB/versions/1.5.1-forge-1.18/entityculling-forge-mc1.18-1.5.1.jar"
	],
	"fileSize": 45276
},

The required, unsupported and optional values in "env": {...,"server": "$VALUE"} are important here, as well as the filename specified.