update bootnodes for mainnet, chronos, and devnet

[vedhavyas]

For mainnet:

• Removed old subspace.network bootnodes and added new autonomys.xyz node
• Old nodes will be shutdown once the there is a new release

For chronos:

• Removed nodes that are not operational anymore

For devet, non-operational but to be conssistent:

• Updated the bootnodes

Code contributor checklist:

• I have read, understood and followed contributing guide

[jfrank-summit]

LGTM