Explorer Solana priority fee and compute budget for outbound.

[ws4charlie]

Describe the Issue
Solana outbound uses fixed fee 5K lamports (Solana default fee per signature) and default 200K compute units. We could explore priority fee and compute budget in future when necessary.

Solana uses micro lamport as the smallest unit of gas price: https://github.com/zeta-chain/node/blob/develop/zetaclient/chains/solana/observer/observer_gas.go#L24
Solana fee: https://solana.com/docs/core/fees#compute-unit-limit
Compute budget: https://solana.com/developers/guides/advanced/how-to-request-optimal-compute

Expected Outcome
A description of what outcome you are seeking.