aur: split into tutabridge-git and tutabridge-bin packages

Add a prebuilt tutabridge-bin package (downloads the published x86_64 CLI
binary, no Rust build) alongside the build-from-source tutabridge-git, each
in its own directory with a PKGBUILD and .SRCINFO. Update the maintainer
address and the packaging README for the two-package layout.

packaging/aur/tutabridge-git/.SRCINFO

@@ -0,0 +1,25 @@
+pkgbase = tutabridge-git
+	pkgdesc = Local IMAP/SMTP bridge for Tuta encrypted email (headless CLI/daemon)
+	pkgver = 0.r0.0000000
+	pkgrel = 1
+	url = https://github.com/spartanz51/tutabridge
+	arch = x86_64
+	arch = aarch64
+	license = GPL-3.0-or-later
+	makedepends = rust
+	makedepends = cargo
+	makedepends = git
+	makedepends = cmake
+	makedepends = nasm
+	makedepends = dbus
+	makedepends = pkgconf
+	depends = gcc-libs
+	depends = dbus
+	optdepends = gnome-keyring: persist the Tuta session across reboots (Secret Service)
+	optdepends = kwallet: alternative Secret Service provider
+	provides = tutabridge
+	conflicts = tutabridge
+	source = tutabridge-git::git+https://github.com/spartanz51/tutabridge.git
+	sha256sums = SKIP
+
+pkgname = tutabridge-git