Querying multiple data streams: Fix the sorting

[dschowta]

Currently the when HDS is queried for multiple data streams, the sorting is not time based, rather it is SenML name based. e.g:

[
    {
      "n": "kitchen/lamp",
      "t": 1583860227.532632,
      "vb": true
    },
    {
      "n": "kitchen/lamp",
      "t": 1583860222.5328066,
      "vb": false
    },
    {
      "n": "terrace/temperature",
      "u": "Cel",
      "t": 1583860227.5185332,
      "v": 19.115799670689995
    },
    {
      "n": "terrace/temperature",
      "u": "Cel",
      "t": 1583860222.5185845,
      "v": 20.56714613731785
    }
]

In the above example, different records with same SenML names are ordered together, which should be ordered in the time based as follows:

[
    {
      "n": "kitchen/lamp",
      "t": 1583860227.532632,
      "vb": true
    },
    {
      "n": "terrace/temperature",
      "u": "Cel",
      "t": 1583860227.5185332,
      "v": 19.115799670689995
    },
    {
      "n": "kitchen/lamp",
      "t": 1583860222.5328066,
      "vb": false
    },
    {
      "n": "terrace/temperature",
      "u": "Cel",
      "t": 1583860222.5185845,
      "v": 20.56714613731785
    }
]

This would be useful especially when the query spans over multiple pages. Then it would be difficult for the clients to wait until the entire package has arrived.