office: Rename mail module to office module

Reflecting the somewhat expanding scope of the module, renamed it to
office. Still keeps the old files and setups but also got a new README
file.

office/.config/msmtp/config

@@ -0,0 +1,18 @@
+# Set default values for all following accounts.
+defaults
+auth           on
+tls            on
+tls_trust_file /etc/ssl/certs/ca-certificates.crt
+# logfile        ~/.msmtp.log
+
+# Gmail
+account        personal-gmail
+host           smtp.gmail.com
+port           587
+from           marty.oehme@gmail.com
+user           marty.oehme@gmail.com
+# password       plain-text-password-goes-here
+passwordeval  "pass show misc/gmail-app-password | head -n1"
+
+# Set a default account
+account default : personal-gmail