[Feature Request] Manage multiple servers in web interface

**Is your feature request related to a problem? Please describe.**
As your project is well design of a server separated from the web interface.
It could be nice to have a way to add multiple servers in the same web interface.

**Describe the solution you'd like**
Add a "Servers" section to add multiples servers.
And then choose on monitors wich server(s) you want to execute the test.
Keep them independant and autonomous with their own notifications (sync notification path?).
This way you can test from different geographics places, all in the same web interface.

**Describe alternatives you've considered**
Install server and web in a complete separate/independent way.

**Additional context**
That's what is used in a product like Zabbix with Zabbix Proxies.
It could be a nice addition.

Look at the server and web interface separation in the codebase, likely in cmd/ and internal/ directories. Understand how monitors and notifications are currently configured per server. Adding a 'Servers' section will require changes to the UI (frontend components) and backend API to manage multiple server instances and associate monitors with specific servers.

Written by the indexing model from the issue text.