Create a charon test mev command to check the performance and connectivity of MEV relays

[boulder225]

🎯 Problem to be solved

We need a way to initially check the performance and connectivity of MEV relays for DV setups to help prevent issues with block production.

🛠️ Proposed solution

• Create a charon test mev command
• Implement an initial check for fast connection to MEV relays
• Add the ability to measure basic response times from relays
• Include this test in the charon setup process
• Provide clear feedback to users about their MEV relay setup quality
• Add documentation explaining the limitations of this test (e.g., performance may vary over time, which could also be related to general mev relay overload)