Added a `--messaging-create-sms-with-text' command line option that works similar to
`--messaging-create-sms-with-data', except that it uses the content of the file as the
message text instead of data.

This allows creating mesasges containing both double and single quotes, which was not
possible with the existing `--messaging-create-sms' command line option.

E.g. in the key-value output:
  modem.3gpp.pco.length   : 2
  modem.3gpp.pco.value[1] : session-id: 1, complete: yes, data: 270180\n
  modem.3gpp.pco.value[2] : session-id: 2, complete: yes, data: 271480802110030100108106503A3DFA8306503A3DFE\n

Or in the human output:
  ----------------------------------
  3GPP     |
           |                    pco: 1: (complete) '270180'

           |                         2: (complete) '271480802110030100108106503A3DFA8306503A3DFE'

  ----------------------------------
  3GPP EPS |   ue mode of operation: csps-2

A network scan with json output currently returns the following:

root@G3-10940 ~ # mmcli -m 0 -J --3gpp-scan --timeout=300 | jq
{
  "modem": {
    "3gpp": {
      "scan-networks": [
        "operator-code: 26201, operator-name: TDG, access-technologies: lte, availability: forbidden",
        "operator-code: 26203, operator-name: o2 - de, access-technologies: lte, availability: forbidden",
        "operator-code: 26202, operator-name: vodafone.de, access-technologies: lte, availability: current"
      ]
    }
  }
}

This is a valid JSON, but in order to be able to access the individual
data elements more easily, the line can also be dumped as a json object.

The following commit converts the lines into a JSON obejct, so that it
looks like this:

root@G3-10940 ~ # mmcli -m 0 -J --3gpp-scan --timeout=300 | jq
{
  "modem": {
    "3gpp": {
      "scan-networks": [
        {
          "operator-code": "26201",
          "operator-name": "TDG",
          "access-technologies": "lte",
          "availability": "forbidden"
        },
        {
          "operator-code": "26203",
          "operator-name": "o2 - de",
          "access-technologies": "lte",
          "availability": "forbidden"
        },
        {
          "operator-code": "26202",
          "operator-name": "vodafone.de",
          "access-technologies": "lte",
          "availability": "current"
        }
      ]
    }
  }
}

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

Fixes #657

Signed-off-by: Frederic Martinsons <frederic.martinsons@gmail.com>

Can be used right away in the mmcli output generation logic.

We're bumping the current "INFO" level messages to the new "MSG"
level, also making the new level the default.

The old "INFO" level will be used to setup an intermediate level of
logging which is not as verbose as "DEBUG" but still provides some
capabilities to analyze the behavior of a modem.