Add manifest file for Mozilla Firefox v80.0 en-US x64 (#3227)

* Add manifest file for Mozilla Firefox v80.0 en-US x64

* Modify manifest file to account for Manifest-Validation Error

manifests/Mozilla/Firefox/Firefox_v80.0/80.0.yaml

@@ -0,0 +1,26 @@
+# ================== General ==================
+
+Id: Mozilla.Firefox.Firefox_v80.0
+Version: 80.0
+Name: Firefox
+Publisher: Mozilla
+AppMoniker: Mozilla Firefox 80.0
+Tags: Mozilla Firefox 80.0
+Description: Mozilla Firefox is free and open source software, built by a community of thousands from all over the world.
+
+# ================== License ==================
+Homepage: https://www.mozilla.org/en-US/firefox/new/
+License: Mozilla Public License Version 2.0
+LicenseUrl: https://www.mozilla.org/en-US/MPL/2.0/
+
+# ================= Installer =================
+Installers:
+  - Arch: x64
+    Url: https://download-installer.cdn.mozilla.net/pub/firefox/releases/80.0/win64/en-US/Firefox%20Setup%2080.0.msi
+    Sha256: f93446a6bd0dd36a58a805c6069516ae8975929e48828f0fcbb258d4b63d48ac
+    InstallerType: msi
+    Switches:
+          Custom: /norestart
+          Silent: /qn
+          SilentWithProgress: /qb
+          Language: en-US