Use PeTTa as interpreter

[rmgaray]

This PR adds execution of MeTTa programs using swipl and PeTTa. The output of the execution of MeTTa programs is captured by f1r3fly, parsed as JSON and then passed to the Rho program as a native data structure.

Example:

$ cargo run --bin rholang-cli -- --quiet rholang/examples/system-contract/swipl/01-compile-metta.rho
{"results" : [["Pair", 3, 1], ["Pair", "y", "x"]]}
Estimated deploy cost: Cost { value: 1269, operation: "subtraction" }