Add builder pattern for the svm

[kevinheavey]

Now we can't call these methods again after instantiating the LiteSVM struct. For example it's nice to be able to call with_compute_budget() multiple times during tests

[Aursen]

Now we can't call these methods again after instantiating the LiteSVM struct. For example it's nice to be able to call with_compute_budget() multiple times during tests

Let's add a set_compute_budget method, for the rest we don't need it in the svm

[kevinheavey]

with_sigverify and with_blockhash_check are also useful to call multiple times (turning them on and off)