Externalize spec typings, use eslint.

Tslint is deprecated, as such we have moved to eslint. Linted the project with more
stringent rules. The configuration will be changed as we figure out which rules we
should keep.

src/index.ts

@@ -12,11 +12,11 @@ import { VersionUtil } from './util/versionutil'
 
 dotenv.config()
 
-function getRoot() {
+function getRoot(): string {
     return resolvePath(process.env.ROOT as string)
 }
 
-function getBaseURL() {
+function getBaseURL(): string {
     let baseUrl = process.env.BASE_URL as string
     // Users must provide protocol in all other instances.
     if (baseUrl.indexOf('//') === -1) {
@@ -63,6 +63,7 @@ function getBaseURL() {
 //     })
 // }
 
+// eslint-disable-next-line @typescript-eslint/explicit-function-return-type
 function namePositional(yargs: yargs.Argv) {
     return yargs.option('name', {
         describe: 'Distribution index file name.',
@@ -101,7 +102,7 @@ const initCommand: yargs.CommandModule = {
     describe: 'Base init command.',
     builder: (yargs) => {
         return yargs
-        .command(initRootCommand)
+            .command(initRootCommand)
     },
     handler: (argv) => {
         argv._handled = true
@@ -117,32 +118,32 @@ const generateServerCommand: yargs.CommandModule = {
     builder: (yargs) => {
         // yargs = rootOption(yargs)
         return yargs
-        .positional('id', {
-            describe: 'Server id.',
-            type: 'string'
-        })
-        .positional('version', {
-            describe: 'Minecraft version.',
-            type: 'string'
-        })
-        .option('forge', {
-            describe: 'Forge version.',
-            type: 'string',
-            default: null
-        })
-        .option('liteloader', {
-            describe: 'LiteLoader version.',
-            type: 'string',
-            default: null
-        })
+            .positional('id', {
+                describe: 'Server id.',
+                type: 'string'
+            })
+            .positional('version', {
+                describe: 'Minecraft version.',
+                type: 'string'
+            })
+            .option('forge', {
+                describe: 'Forge version.',
+                type: 'string',
+                default: null
+            })
+            .option('liteloader', {
+                describe: 'LiteLoader version.',
+                type: 'string',
+                default: null
+            })
     },
     handler: async (argv) => {
         argv.root = getRoot()
 
         console.debug(`Root set to ${argv.root}`)
         console.debug(`Generating server ${argv.id} for Minecraft ${argv.version}.`,
-        `\n\t├ Forge version: ${argv.forge}`,
-        `\n\t└ LiteLoader version: ${argv.liteloader}`)
+            `\n\t├ Forge version: ${argv.forge}`,
+            `\n\t└ LiteLoader version: ${argv.liteloader}`)
 
         if (VersionUtil.isPromotionVersion(argv.forge as string)) {
             console.debug(`Resolving ${argv.forge} Forge Version..`)
@@ -197,8 +198,8 @@ const generateCommand: yargs.CommandModule = {
     describe: 'Base generate command.',
     builder: (yargs) => {
         return yargs
-        .command(generateServerCommand)
-        .command(generateDistroCommand)
+            .command(generateServerCommand)
+            .command(generateDistroCommand)
     },
     handler: (argv) => {
         argv._handled = true
@@ -273,14 +274,14 @@ const testCommand: yargs.CommandModule = {
 // Registering yargs configuration.
 // tslint:disable-next-line:no-unused-expression
 yargs
-.version(false)
-.scriptName('')
-.command(initCommand)
-.command(generateCommand)
-.command(validateCommand)
-.command(latestForgeCommand)
-.command(recommendedForgeCommand)
-.command(testCommand)
-.demandCommand()
-.help()
-.argv
+    .version(false)
+    .scriptName('')
+    .command(initCommand)
+    .command(generateCommand)
+    .command(validateCommand)
+    .command(latestForgeCommand)
+    .command(recommendedForgeCommand)
+    .command(testCommand)
+    .demandCommand()
+    .help()
+    .argv