Update mobile-proof-of-coverage.mdx

[heatedlime]

Made the below changes-

• Incorporated Wi-Fi
• Discussed SP Hex Boosting
• Discussed HIP 85 Hex Limits -Edited roadmap for POC -Introduced the concept of Oracle hex boosting

I still need to add the HIP 103 multipliers, but need to figure out how to upload an image first.