Introduce wrapper function to ease HTS setup

[Luis Mastrangelo]

Currently, our HTS setup looks like the following

deployCodeTo("HtsSystemContractJson.sol", HTS_ADDRESS);
HtsSystemContractJson(HTS_ADDRESS).setMirrorNodeProvider(new MirrorNodeFFI());
vm.allowCheatcodes(HTS_ADDRESS);

This exposes some implementation details that the user shouldn't worry about. Wrap this snippet into a function to ease HTS setup for users.