move deploy.py file and revamp README

deploy-chatmail/src/deploy_chatmail/deploy.py

@@ -0,0 +1,19 @@
+import os
+import pyinfra
+from deploy_chatmail import deploy_chatmail
+
+
+def main():
+    mail_domain = os.getenv("CHATMAIL_DOMAIN")
+    mail_server = os.getenv("CHATMAIL_SERVER", mail_domain)
+    dkim_selector = os.getenv("CHATMAIL_DKIM_SELECTOR", "2023")
+
+    assert mail_domain
+    assert mail_server
+    assert dkim_selector
+
+    deploy_chatmail(mail_domain, mail_server, dkim_selector)
+
+
+if pyinfra.is_cli:
+    main()