Provide an About Page to Show Version of Parser

[jvanderaa]

Environment

• Nautobot version: 1.5.8
• nautobot-circuit-maintenance version: Latest

Proposed Functionality

Add an about page to show the underlying Python Circuit Maintenance Parser Library that is installed.

Use Case

The plugin menu shows what version of the plugin is installed, but not what version of the parser library is installed. We should be able to determine what version of the library is installed as there are likely to be version updates quicker on the Python parsing library than the plugin itself.