Add /info URL to provide information about server application

[dwywdo]

There's ManagementService to provide functionality for thread & heap dump via /jvm/threaddump and /jvm/heapdump

• armeria/core/src/main/java/com/linecorp/armeria/server/management/ManagementService.java

  Lines 76 to 79 in 53526d7

  	case "/jvm/threaddump":
  	return ThreadDumpService.INSTANCE.serve(ctx, req);
  	case "/jvm/heapdump":
  	return HeapDumpService.INSTANCE.serve(ctx, req);

How about providing information about deployed Armeria version, as well as service application's version such as below?

{
  "app" : {
    "version" : "1.0.0",
    "description" : "..",
    "name" : "short name"
  },
  "armeria": {
     "version": ...
     "commit": ...
   }

app information could be configured by adding method such as setAppInfo in ServerBuilder so that user can pass required information that can be queried via /info URL

[Leewongi0731]

Could I take this issue??

[dwywdo]

Sorry actually I'm working on this now 😅