datajson: add remove_key option to dataset

datajson: add remove_key option to dataset

This option allows to remove the key corresponding to the match
value from the JSON object before creating the JSON object that
will be added to the `extra` data.

For example, matching on the following JSON on the `ip` key:

```json
{"ip": "10.16.1.11", "test": "success", "context":3}
```

with a match like:

```
dataset:isset,src_ip,type ip,load src.lst,format jsonline,enrichment_key src_ip,value_key ip;
```

will produce the following:

```json
"extra": {
  "src_ip": {
    "ip": "10.16.1.11",
    "test": "success",
    "context": 3
  }
```

if we add the `remove_key` option to the match:

```
dataset:isset,src_ip,type ip,load src.lst,format jsonline,enrichment_key src_ip,value_key ip, remove_key;
```

it will produce the following:

```json
"extra": {
  "src_ip": {
    "test": "success",
    "context": 3
  }
```

The option is set to false by default.

Ticket: #7372