Admin vesting features

[RustNinja]

Added 4 functions that introduced new features:

• admin is able to remove vesting schedule for someone who already started vesting. admin_remove_claim
• admin is able to remove vesting schedule for someone who did not start vesting yet. admin_remove_new_claim
• admin is able to introduce vesting plan for any solana pub key. admin_new_claim
• user now able to claim and start vesting once admin give that user new vesting plan. claim_new_claim