Add ChainUp Back to RPC providers

[chainupcloud]

#2299

Add ChainUp Back to RPC providers

I wanted to clarify that ChainUp still supports both Filecoin mainnet and calibration testnet.
I would like to appeal for the re-addition of ChainUp as an RPC provider. It has come to my attention that there may have been doubts about their support for the Filecoin network.

I can confirm that ChainUp continues to support both the Filecoin Mainnet and the Calibration Testnet. Their services provide reliable access for users looking to connect to these networks, ensuring a seamless experience for developers and users alike.

I believe it would be beneficial for the community to have ChainUp listed again as an RPC provider. Thank you for considering this request!

[smagdali]

Pending @eshon's agreement, feel free to raise a PR.

[ArseniiPetrovich]

But the Chainup is still in the Filecoin docs, they were not removed.
I created #2337 to replace few others and open to discussions there.
@eshon also very welcomed there