add more builtin scenarios

[zeroXbrock]

Is your feature request related to a problem? Please describe.

Most of the scenarios I've written so far have used high-volume-contract at their core (it contains the SpamMe contract). The fill-block spam subcommand relies on it as well.

It would be nice to have that contract be tightly coupled with contender as we add more subcommands and iterate on the contract.

Describe the solution you'd like

• add high-volume-contracts to this repo (NOT as a submodule)
• load bytecode for builtin scenarios from build artifacts (AT compile-time)
• add more subcommands to spam
  • precompile [precompile_name]
  • opcode [opcode_name]
  • storage [num_slots, writes_per_tx, reads_per_tx, ...get creative w/ more options.]
  • ...