Enforce stellar-core limits during testing

[sisuresh]

What problem does your feature solve?

Currently, only cpu and memory limits are enforced during testing because those two limits are tracked in the host. Limits like the entry and byte limits are enforced in core, so contract tests using the sdk are not affected by these limits. The issue with this is that a contract developer will not realize those limits are an issue until after they deploy their contract to testnet, potentially resulting in wasted time developing a contract that doesn't work.

We should allow the sdk testutils to set and enforce limits just like the ones in core (read_entries, write_entries, read_bytes, write_bytes, and contract_events_size_bytes).