add another subpath level to values.yaml oap config override

[ScribblerCoder]

@kezhenxu94's PR was a great enhancement that gave the ability to set oap config override files from within values.yaml. But it only allows us to override files that are up to 1 level deep under /skywalking/config.

For example:

• alarm-settings.yaml is directly under /skywalking/config which is 0 levels deep
• core.oal is under /skywalking/config/oal/ which is 1 level deep

Why this PR?
SkyWalking has some configuration files like:

• /skywalking/config/ui-initialized-templates/general/*
• /skywalking/config/openapi-definitions/serviceA/*
  Which are 2 levels deep and we need to have the ability to set them through values.yaml. So I just added one more level and now we can set override oap configurations this way

2 levels

    ui-initialized-templates:
      general:
        general-service.json: |
          [{"id":"General-Service" ........

1 level

     oal:
       core.oal: |
         service_resp_time = from(Service.latency).longAvg();
         service_sla = from(Service.*).percent(status == true);
         service_cpm = from(Service.*).cpm(); 
         ................

0 levels

    alarm-settings.yml: |
      rules:
        service_resp_time_rule:
          expression: sum(service_ .....
          .........

[kezhenxu94]

Thanks, looks good.