Use solana-cli config keypair in solana-keygen (#8074)

* Use solana-cli config keypair in solana-keygen

* s/infile/keypair for consistency across modules and more generality across access methods

* Move config into separate crate

cli/src/lib.rs

@@ -1,9 +1,5 @@
-#[macro_use]
-extern crate lazy_static;
-
 pub mod cli;
 pub mod cluster_query;
-pub mod config;
 pub mod display;
 pub mod nonce;
 pub mod offline;