Add an API endpoint for GETing server version

This commit adds an API endpoint to get the server version. This will be
used to add the ability for the mobile app to show which server version
the server you are currently connected to is running.

server/controllers/MiscController.js

@@ -159,6 +159,15 @@ class MiscController {
     res.json(downloads)
   }
 
+  // GET: api/version
+  async getServerVersion(req, res) {
+    var version = {
+      serverVersion: this.db.serverSettings.version
+    }
+
+    return res.json(version)
+  }
+
   // PATCH: api/settings (admin)
   async updateServerSettings(req, res) {
     if (!req.user.isAdminOrUp) {

server/routers/ApiRouter.js

@@ -202,6 +202,7 @@ class ApiRouter {
     this.router.delete('/download/:id', MiscController.removeDownload.bind(this))
     this.router.get('/downloads', MiscController.getDownloads.bind(this))
     this.router.patch('/settings', MiscController.updateServerSettings.bind(this)) // Root only
+    this.router.get('/version', MiscController.getServerVersion.bind(this))
     this.router.post('/purgecache', MiscController.purgeCache.bind(this)) // Root only
     this.router.post('/authorize', MiscController.authorize.bind(this))
     this.router.get('/search/covers', MiscController.findCovers.bind(this))