Client: ignore service network

[magicnat]

A special network, 000_svc will be created by the emulator if an emulation uses services that require real-world network interactions, like routing traffic to real-world or remote network access. This network will appear on the client topology map, which can be confusing. Consider hiding this network from the users unless specified.

We also should create a new tab for client-side settings on the map page. Hiding/showing special service networks like this can be an option. If we were to implement #24, we would also need this options panel to toggle the layers.

[magicnat]

Closing: implemented in a67efbe.