cmd: CMD option for port number of gogs web to prevent first time run conflict

- routers: use new binding convention to simplify code
- templates: able to set HTTP port number in install page

conf/app.ini

@@ -1,3 +1,6 @@
+# NEVER EVER MODIFY THIS FILE
+# PLEASE MAKE CHANGES ON CORRESPONDING CUSTOM CONFIG FILE
+
 ; App name that shows on every page title
 APP_NAME = Gogs: Go Git Service
 ; Change it if you run locally

conf/locale/locale_en-US.ini

@@ -59,6 +59,8 @@ run_user = Run User
 run_user_helper = The user must have access to Repository Root Path and run Gogs.
 domain = Domain
 domain_helper = This affects SSH clone URLs.
+http_port = HTTP Port
+http_port_helper = Port number which application will listen on.
 app_url = Application URL
 app_url_helper = This affects HTTP/HTTPS clone URL and somewhere in e-mail.
 email_title = E-mail Service Settings (Optional)