Extract loader-v2-interface crate

[kevinheavey]

Problem

solana_program::loader_instruction imposes a solana_program dep on solana_transaction_status.

Summary of Changes

• Move to a new crate and re-export for backwards compatibility. I called this one solana-loader-instruction instead of solana-loader-interface because the instruction module is the only thing in the crate
• Update solana-transaction-status to use the new crate

[joncinque]

Looks good! Just the naming bit

[joncinque]

nit: can we call this solana-loader-v2-interface? the v2 bit so that people are less tempted to use it, especially when they see v3 and v4, and interface for consistency with the other loader crates, even though there's no state.

I could even be convinced to go with v1 since they share an interface.

[joncinque]

is this feature needed?

[joncinque]

Looks great, thanks!

[joncinque]

@yihau can you accept ownership of solana-loader-v2-interface?

[Lichtso]

loader-v2 program management has been deactivated for a while (a year or longer). Why not remove it entirely?

[kevinheavey]

would be a breaking change in solana-program and solana-sdk

[Lichtso]

Yes, but what about the deprecated attribute. It says you should use the moved crate. But it should say that this functionality is gone and will be completely removed.