Add "VPN Connections" in Nautobot

[JHarrison712]

Feature Request: Introduce VPN Connections as a Category in Nautobot

Proposal

Introduce VPN Connections as a dedicated category in Nautobot.

Current Behavior

Currently, VPN-related categories include:

• Tunnels
• Tunnel Groups
• Tunnel Terminations
• L2VPNs

However, there's no direct way to manage VPN Connections, which is essential for network operations.

Proposed Change

• Add VPN Connections as a separate entity or category.
• Allow linking VPN Connections with tunnels, groups, and terminations.

Benefits

• Provides a clear distinction between VPN infrastructure and active connections.
• Helps with better VPN monitoring and management.
• Streamlines VPN-related configurations in Nautobot.

Would love feedback from the community on this idea!

[cardoe]

Related to #915 and https://github.com/orgs/nautobot/discussions/4531