[Task] Support for editting target details

[tthvo]

It looks like the users cannot edit labels/annotations of target. Most targets now have empty labels. It would be nice to be able to support this.

{
  "alias": "io.cryostat.Cryostat",
  "annotations": {
      "cryostat": {
          "HOST": "cryostat",
          "JAVA_MAIN": "io.cryostat.Cryostat",
          "PORT": "9091",
          "REALM": "JDP"
      },
      "platform": {}
  },
  "connectUrl": "service:jmx:rmi:///jndi/rmi://cryostat:9091/jmxrmi",
  "jvmId": "71i3ivTX0ucC9BzsZTMd3ySSPX3q3azC-sgrs5-yV54=",
  "labels": {}
}