Add text file export of Pathauto configuration for debugging

A lot of the time when people submit issues users have to go back and forth in the issue about what the settings are. It would be nice if the Pathauto help text linked to a page that dumped out a bunch of information which they could put in a text file and attach to the issue. This way we would know all their settings from the beginning.

This could also be useful to see how many people have changed their variables from the defaults or how many are using new settings. If nobody changes the default on a field then perhaps we should hide that from the UI. Similarly, if everyone is changing a field to a new consistent value maybe we could have a different default. Providing an easy way for people to submit that information in a formatted manner would provide the data we need to make decisions like this.

Things to include:
1. All variables from the variable table with a name like '%pathauto%'
2. The values from the system tabale for name = 'pathauto'

Anything else?