feat: support _meta.pre_function to execute custom logic before execution of each phase #979

Job	Run time
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/http3/admin)	3m 25s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	3m 26s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	3m 26s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yaml...	3m 26s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script ...	3m 26s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/http3/admin)	3m 25s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	3m 20s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	3m 24s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/cont...	3m 25s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secre...	3m 25s
	34m 8s

Provide feedback