Support ArchLinux level-2 enroll; Add intune-portal pkg; Add instructions & FAQ

This PR adds necessary package & instructions to support level-2 enrollment on ArchLinux. Manjaro Linux is still pending for testing.

intune-portal/PKGBUILD

 # Maintainer: Recolic K <root@recolic.net>
 
 pkgname=intune-portal
-pkgver=1.2310.8
+pkgver=1.2312.35
 pkgrel=0
 pkgdesc="Microsoft Intune helps organizations manage access to corporate apps, data, and resources."
 url="https://packages.microsoft.com/ubuntu/20.04/prod/pool/main/i/intune-portal"
@@ -13,9 +13,9 @@ makedepends=()
 conflicts=()
 replaces=()
 backup=()
-source=("source.deb::$url/${pkgname}_${pkgver}_amd64.deb")
+source=("source.deb::$url/${pkgname}_${pkgver}-focal_amd64.deb")
 validpgpkeys=("")
-sha256sums=("001d0903f26b78a705f36f278df584d9126a7feafc91a70810e814c60460842a")
+sha256sums=("501005d25714a1a3e26d7a2b4a2eac677ace8edd0b5869cd152308fd69bc4a61")
 install=x.install
 
 package() {