feat: etherscan like api to get contract source code #83

All 1 778 tests pass, 1 skipped in 2m 51s

      3 files +    1   234 suites +66 2m 51s ⏱️ + 1m 39s
1 779 tests +656 1 778 ✔️ +656 1 💤 ±0 0 ❌ ±0
1 804 runs +677 1 803 ✔️ +677 1 💤 ±0 0 ❌ ±0

Results for commit 1dc69d0. ± Comparison against earlier commit a284d6c.