Provide a firejail profile for mutt

This is part of hashbang/shell-etc#86

.config/firejail/mutt.profile

@@ -0,0 +1,28 @@
+# Firejail profile for mutt
+
+# In case GnuPG is called
+noblacklist ~/.gnupg
+mkdir ~/.gnupg
+whitelist ~/.gnupg
+
+# Allow access to mailboxes
+whitelist ~/Mail
+whitelist ~/sent
+whitelist ~/postponed
+
+# Allow executing /usr/sbin/sendmail
+noblacklist /usr/sbin
+
+# Generic sandboxing
+caps.drop all
+seccomp
+protocol unix,inet,inet6
+netfilter
+tracelog
+nonewprivs
+noroot
+
+include /etc/firejail/disable-common.inc
+include /etc/firejail/disable-passwdmgr.inc
+include /etc/firejail/disable-programs.inc
+include /etc/firejail/disable-devel.inc