Policy: Report reason inputs are non standard
This PR is another attempt at #13525.
Transactions that fail PreChecks Validation due to non-standard inputs now returns invalid validation stateTxValidationResult::TX_INPUTS_NOT_STANDARD along with a debug error message.
Previously, the debug error message for non-standard inputs do not specify why the inputs were considered non-standard.
Instead, the same error string, bad-txns-nonstandard-inputs, used for all types of non-standard input scriptSigs.
This PR updates the AreInputsStandard to include the reason why inputs are non-standard in the debug message.
This improves the Precheck debug message to be more descriptive.
Furthermore, I have addressed all remaining comments from #13525 in this PR.