feat(metrics): add metrics for last event receipt timestamps (#2223) #2715

Job	Run time
test (api)	10m 21s
test (bns)	3m 35s
test (bns-e2e)	7m 14s
test-rosetta (rosetta)	3m 13s
lint	1m 3s
test-rosetta (rosetta-construction)	2m 16s
test (btc-faucet)	1m 40s
test-rosetta (rosetta-cli-data)	2m 4s
test-2_5 (block-zero-handling)	1m 31s
test (event-replay)	2m 3s
test (rpc)	1m 35s
test-2_5 (faucet-stx)	1m 30s
test-rosetta (rosetta-cli-construction)	2m 25s
test-2_5 (pox-4-btc-address-formats)	2m 14s
test-2_5 (pox-4-delegate-aggregation)	2m 8s
test-2_5 (pox-4-delegate-stacking)	1m 42s
test-2_5 (pox-4-delegate-revoked-stacking)	2m 3s
test-2_5 (pox-4-stack-extend-increase)	2m 20s
test-2_5 (pox-4-rosetta-btc-addr-types)	4m 53s
test-2_5 (pox-4-rosetta-cycle-phases)	1m 18s
test-2_5 (pox-4-rosetta-segwit)	1m 38s
test-2_5 (pox-4-burnchain-stack-stx)	1m 39s
test-2_5 (pox-4-burnchain-delegate-stx)	1m 39s
build-publish	0s
	1h 2m 4s

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