Execution options for processor and prover

[bobbinth]

In some situations, we may want to provide additional info to the processor on how to execute a program. For example, we may want to specify the maximum number of cycles a program is allowed to consume (see #648). Or if we have some idea of how many cycles a program may execute for, we may give this hint to the processor so that it can allocated the required amount of memory upfront.

We can do this by updating processor::execute() function to look as follows:

pub fn execute<A>(
    program: &Program,
    stack_inputs: StackInputs,
    advice_provider: A,
    options: ExecutionOptions,
) -> Result<ExecutionTrace, ExecutionError>
where
    A: AdviceProvider,

Where ExecutionOptions could look like this:

pub struct ExecutionOptions {
    max_cycles: Option<u32>,
    expected_cycles: u32, // defaults to 64 if not specified
}

We will also need to update the ProofOptions currently accepted by prover::prove() function like so (and maybe rename it to ProvingOptions):

pub struct ProofOptions {
    pub hash_fn: HashFunction,
    pub exec_options: ExecutionOptions,
    pub proof_options: WinterProofOptions,
}

[bobbinth]

Closed by #991 and #998.