Upgrade to Solana v1.18

[joncinque]

Problem

sys is still using 1.17 crates, even though 2.0 is about to hit mainnet.

Summary of changes

• 7489fbd: It was a big change to upgrade to v2.0 directly, so only upgrade to v1.18 for now. During the upgrade to v2.0, the calls to get_stake_activation need to updated to use the client-side helper: https://github.com/anza-xyz/solana-rpc-client-extensions -- I can take care of that as follow-up work.
• 1a53669: Remove the direct dependency on solana_vote_program as mentioned in one of the comments
• 5e2ea36: since the get_fees RPC method was removed, I removed its usage, opting for get_fee_for_message instead <-- this is the most important change, since sys fails against mainnet right now because of this

[mvines]

Awesome, thanks!

[mvines]

Some clippy stuff in dependencies, gonna merge on red though

[joncinque]

I had initially fixed that too, but didn't want to add too much in the PR -- you just need to add test and client features in Cargo.toml