feat: Adds draft design doc for new block explorer REST API endpoints #7691

All 1 tests pass in 1m 0s

1 files - 25 5 suites - 373 1m 0s ⏱️ - 1h 1m 11s
1 tests - 617 1 ✅ - 586 0 💤 - 4 0 ❌ - 27
1 runs - 1 129 1 ✅ - 1 095 0 💤 - 4 0 ❌ - 30

Results for commit f1be973. ± Comparison against earlier commit 800e769.