Remove legacy functions form IKeystoreService.aidl

In preparation for making the keystore service asynchronous we remove
redundant legacy functionality from the protocol.

This patch removes the functions get_pubkey, sign, verify, generate,
and import_key. Which have long been superseded by exportKey
(get_pubkey), begin/update/finish (sign, verify), generateKey
(generate), and importKey (import_key).

This patch also removes isOperationAuthorized.

Test: KeyStore CTS tests
Bug: 111443219
Change-Id: Ib3bd6f40b4e948e5ad6b2ef5278b18ff46201d71