Tie data exports to mod packs

Store the export manifest in ModPack to allow mulitple mod packs to have
different data exported. This is necessary as the export contains the
settings prototypes needed to create a proper UI for mod settings.

For now the useLocale and useItemMetadata interfaces uses the manifest
for a default mod pack set in the master config.

test/lib/data/ModPack.js

@@ -3,6 +3,7 @@ const assert = require("assert").strict;
 const zlib = require("zlib");
 
 const libSchema = require("@clusterio/lib/schema");
+const ExportManifest = require("@clusterio/lib/data/ExportManifest");
 const ModPack = require("@clusterio/lib/data/ModPack");
 
 
@@ -18,6 +19,7 @@ describe("lib/data/ModPack", function() {
 				assert.deepEqual(new ModPack(json), pack);
 				const packStringed = ModPack.fromModPackString(pack.toModPackString());
 				packStringed.id = pack.id;
+				packStringed.exportManifest = pack.exportManifest;
 				assert.deepEqual(packStringed, pack);
 			}
 
@@ -40,6 +42,7 @@ describe("lib/data/ModPack", function() {
 					"string-setting": { "value": "a string" },
 				},
 			}}));
+			check(new ModPack({ export_manifest: { assets: { setting: "settings.json" }}}));
 			check(new ModPack({ deleted: true }));
 			check(new ModPack({
 				name: "Super pack",
@@ -60,6 +63,7 @@ describe("lib/data/ModPack", function() {
 						"string-setting": { "value": "a string" },
 					},
 				},
+				export_manifest: { assets: { setting: "settings.json" }},
 				deleted: true,
 			}));
 		});