Web-based file editor for $OPENNMS_HOME/etc/

Provide a solution that allows OpenNMS administrators to edit configuration files from $OPENNMS_HOME/etc/ via the Web UI.

This is intended to be used as a stop-gap solution to allow users to configure the solution from the Web UI until alternatives are present.

Requirements:

• Provide the ability to edit or create any files in $OPENNMS_HOME/etc/ with the following extensions: .xml, .properties, .cfg, .drl, .groovy, .bsh
• Restrict access to UI component and REST APIs to users with the ADMIN role

Nice to haves:

• Provide the ability to view log files (to help assess and debug config changes)
• Provide basic forms of input validation
• Easily identify files that have changes when compared to $OPENNMS_HOME/share/etc-pristine