Enhance explorer observations with chain time #2950

Job	Run time
Build haddock using nix	1m 14s
Benchmarks (hydra-node, tx-cost, --output-directory $(pwd)/../benchmarks)	2m 56s
Benchmarks (hydra-node, micro, -o $(pwd)/../benchmarks/ledger-bench.html)	1m 57s
Build & test (plutus-cbor)	1m 35s
Benchmarks (hydra-cluster, bench-e2e, datasets datasets/3-nodes.cbor datasets/1-node.cbor --outpu...	5m 13s
Build & test (plutus-merkle-tree)	1m 19s
Benchmarks (plutus-merkle-tree, on-chain-cost, $(pwd)/../benchmarks)	1m 36s
Build & test (hydra-plutus)	1m 17s
Build specification using nix	45s
Build & test (hydra-tui)	2m 31s
Build & test (hydra-node)	4m 1s
Build & test (hydra-cluster)	10m 17s
Publish benchmark results	5s
Documentation	1m 23s
Publish test results	14s
	36m 23s

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