feat: add Xahau mainnet and testnet networks

[WietseWind]

High Level Overview of Change

• Change Hooks terminology (network) to Xahau
• Instead of Hooks Testnet, add Xahau mainnet & testnet

Context of Change

• 1x dropdown (network) change
• 1x dropdown (network) add
• env vars & small bits of code changed from hooks to Xahau, while keeping the reference to executed Hooks etc. in place

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (You added tests for code that already exists, or your new feature included in this PR)
• Documentation Updates
• Translation Updates
• Release

Note

Websocket endpoints:

Mainnet: wss://xahau.network
Testnet: wss://xahau-test.net