APT-1653: ZQ2 protomainnet connected

[lukozill]

Description

Functional changes:

• Zillion now recognizes when ZilPay is connected to Protomainnet and uses the appropriate configuration
• Blockchain data loading split into multiple steps, so now it does not look broken cause of long fetching times
• In case of loading errors (e.g., API unresponsive), the webpage now indicates that

Minor changes:

• Config for ZQ2 protomainnet added to all cloud stages. So, after deployment, everybody can test on https://stake.zilliqa.com
• Network configuration improved. Recognition is now based on the API URL instead of the ZilPay network name to enable proto networks. The code got refactored, so most of the things are now hardcoded in config-helper.ts
• blockchain_explorer_config removed. This was redundant as we are only using one explorer per chain.
• Zilliqa API instance creation code simplified (e.g., ApiRandomize removed)
• console.warn replaced with console.error so we actually see the errors

Testing

• The npm run build works
• I've tested the application with ZilPay connected to ZQ2 Protomainnet. I was able to stake. I couldn't do unstaking, but that looks like an issue with the Network, not the application. Therefore, we can merge this one, as it delivers value beyond just adding ZQ2 Protomainnet.