feat(log-serializer): add latencies.receive property to log-serializer

[flrgh]

Summary

This adds receive time to the latencies object, as reported in ctx.KONG_RECEIVE_TIME:

kong/kong/init.lua

Lines 1685 to 1692 in 15a3797

	-- time spent receiving the response ((response +) header_filter + body_filter)
	-- we could use $upstream_response_time but we need to distinguish the waiting time
	-- from the receiving time in our logging plugins (especially ALF serializer).
	ctx.KONG_RECEIVE_TIME = ctx.KONG_BODY_FILTER_ENDED_AT - (ctx.KONG_RESPONSE_START or
	ctx.KONG_HEADER_FILTER_START or
	ctx.KONG_BALANCER_ENDED_AT or
	ctx.KONG_BALANCER_START or
	ctx.KONG_ACCESS_ENDED_AT)

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• There is a user-facing docs PR (link)

Issue reference

KAG-3798

[nowNick]

Nice 🚀 !

[team-gateway-bot]

Successfully created cherry-pick PR for master:

• https://github.com/kong/kong-ee/pull/8528

[gszr]

Note that the scope here must be PDK in the changelog