feat: restore InitializeAccount3 instruction

[sonicfromnewyoke]

i came across your pinocchio realization of the CPI client to token2022 program and just restored the instruction.

in case you doesn't need it - just close the MR with removing initialize_account_3.rs from the source code.

Also, what do you think about moving this CPI client under the pinocchio repo?

[pkxro]

+1 to moving the CPI client, cc: @deanmlittle -- seems like a better home

[sonicfromnewyoke]

i guess, it's worth leaving here a reference to this MR