feat: rewrite hmac-auth plugin for usability #16913

Job	Run time
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	34m 58s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	34m 46s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yaml...	26m 2s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script ...	25m 59s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	9m 36s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	37m 9s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/cont...	25m 59s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secre...	26m 1s
	3h 40m 30s

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