feat: add token support for consul_kv discovery(#9532)

[hulining]

Description

This PR supports the consul_kv service discovery support token function described in #9532.

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
  For testing, I don't know how to add test cases yet, but I tested locally that this function can be used normally.
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[leslie-tsang]

Hello there, we need a test case for this feature. :)

[sevensolutions]

I'am really waiting for this feature.
Where can we find the existing tests for the consul DNS provider, so i check what we need to add?

Edit: Ah, found it. They're here:
https://github.com/apache/apisix/blob/master/t/discovery/consul.t
https://github.com/apache/apisix/blob/master/t/discovery/consul_kv.t

I have no idea how to execute them right now, but i'll try to provide some tests here.

[monkeyDluffy6017]

@leslie-tsang please help to finish this pr

[sevensolutions]

I think i'am almost there. What i've done:

1. Added a new consul service to ci/pod/docker-compose.first.yml which enables ACL

consul_3:
    image: consul:1.15.4
    restart: unless-stopped
    ports:
      - "8502:8500"
    command: [ "consul", "agent", "-server", "-bootstrap-expect=1", "-client", "0.0.0.0", "-log-level", "info", "-data-dir=/consul/data", "-enable-script-checks", "-ui", "-hcl", "acl = {\nenabled = true\ndefault_policy = \"deny\"\nenable_token_persistence = true\n}" ]
    networks:
      consul_net:

2. Run make ci-env-up project_compose_ci=ci/pod/docker-compose.first.yml
3. Added a new test in t/discovery/consul.t to bootstrap the ACL system

=== TEST 14: bootstrap acl
--- config
location /v1/acl {
    proxy_pass http://127.0.0.1:8502;
}
--- request eval
[
    "PUT /v1/acl/bootstrap\n" . "{\"BootstrapSecret\": \"2b778dd9-f5f1-6f29-b4b4-9a5fa948757a\"}"
]
--- error_code eval
[200]

3. Then i've just copied one of the other tests.
4. Executed tests with TEST_NGINX_BINARY=/usr/bin/openresty prove -It/test-nginx/lib -I./ -r t/discovery/consul.t

Is this the correct way to go?

[monkeyDluffy6017]

@sevensolutions Yeah, it's exactly what you said

[sevensolutions]

@monkeyDluffy6017 thanks.

How can i get some logs from APISIX during development?
I'am getting a 500 Internal Server Error when i run curl "http://127.0.0.1:9180/apisix/admin/services/" -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' but i have no idea why.
Is there a special API-Key used in the development version?
I just started APISIX with make run

Edit: Found it.
I'am getting:

2023/09/26 19:05:19 [error] 1253677#1253677: exit_worker_by_lua error: ./apisix/plugins/ext-plugin/init.lua:18: module 'flatbuffers' not found:
no file '/home/daniel/apisix2/apisix//deps/share/lua/5.1/flatbuffers.lua'

[sevensolutions]

Got it working. I've created #10278 for token support in consul including tests.

[monkeyDluffy6017]

Thanks for your contribution! I'will close this pr, it's done by #10278