feat: 🎸 added application import feature

Now it is possible to import a list of applications with variants from a
json input file

src/cmds/app-cmds/import.ts

@@ -0,0 +1,75 @@
+import {Arguments, Argv} from 'yargs';
+import {UPSAdminClientFactory} from '../../utils/UPSAdminClientFactory';
+import * as fs from 'fs';
+import {PushApplication, Variant} from '@aerogear/unifiedpush-admin-client';
+export const command = 'import';
+
+export const describe =
+  'Import a list of applications from a json file together with their variants. Such file can be the json output of the list command';
+
+export const builder = (yargs: Argv) => {
+  return yargs
+    .group(['in', 'output'], 'Import applications:')
+    .option('in', {
+      required: true,
+      type: 'string',
+      describe:
+        'Path to the json file containing the applications to be imported.',
+      requiresArg: true,
+    })
+    .help();
+};
+
+export const handler = async (argv: Arguments) => {
+  const fileToString = (filePath: string): string =>
+    fs.readFileSync(filePath, 'utf8');
+
+  const appList: PushApplication[] = JSON.parse(
+    fileToString(argv.in as string)
+  );
+
+  const newApps: PushApplication[] = [];
+
+  await Promise.all(
+    appList.map(async oldApp => {
+      const variants: Variant[] = oldApp.variants || [];
+      oldApp.variants = [];
+      variants.forEach(v => {
+        const vtmp = v as Record<string, string>;
+        delete vtmp.id;
+        delete vtmp.variantID;
+      });
+
+      const newAppDefinition = ({...oldApp} as unknown) as Record<
+        string,
+        string
+      >;
+      delete newAppDefinition['pushApplicationID'];
+      delete newAppDefinition['id'];
+
+      try {
+        // creating the apps
+        const newApp = await UPSAdminClientFactory.getUpsAdminInstance(argv)
+          .applications.create('')
+          .withDefinition(newAppDefinition)
+          .execute();
+        newApps.push(newApp);
+
+        for (const v of variants) {
+          await UPSAdminClientFactory.getUpsAdminInstance(argv)
+            .variants[v.type].create(newApp.pushApplicationID)
+            .withDefinition((v as unknown) as never)
+            .execute();
+        }
+      } catch (err) {
+        77;
+        console.log(
+          'Failed importing app with ID',
+          oldApp.pushApplicationID,
+          err
+        );
+      }
+    })
+  );
+  console.log(`${newApps.length} application(s) imported`);
+};