Move `solana_sdk::pubkey` functions to solana-pubkey #5803

Job	Run time
android (ubuntu-20.04, x86_64-linux-android)	2m 46s
android (ubuntu-20.04, aarch64-linux-android)	2m 55s
android (ubuntu-20.04, i686-linux-android)	2m 53s
android (ubuntu-20.04, armv7-linux-androideabi)	3m 7s
ios (macos-12, aarch64-apple-ios)	4m 6s
ios (macos-12, x86_64-apple-ios)	5m 43s
ios (macos-12, aarch64-apple-darwin)	7m 46s
ios (macos-12, x86_64-apple-darwin)	4m 44s
error_reporting	0s
	34m 0s

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