Encode connection ID for the URL path

[teclator]

Problem

The CLI needs to encode the connection Id in order to use it in the URL for adding or updating it.

• https://bugzilla.suse.com/show_bug.cgi?id=1246930
• https://trello.com/c/H8mxZJxy/5185-2-agama-loading-a-profile-tries-to-create-an-existing-network-

Solution

Encode the connection id in order to use it in the URL path for adding or updating a connection

Testing

• Tested manually
  Example profile net.json

suse@vikingo:~$ cat net.json 
{
  "product": {
    "id": "Tumbleweed"
  },
  "network": {
    "connections": [
      {
        "id": "Wired #1",
        "status": "up"
      }
    ]
  }
}

suse@vikingo:~$ agama config load < net.json 
✓ The profile is valid.

suse@vikingo:~$ agama config load < net.json 
✓ The profile is valid.

## REMOVED IRRELEVANT DATA
suse@vikingo:~$ agama config show 
{
  "network": {
    "connections": [
      {
        "id": "Wired #1",
        "method4": "auto",
        "method6": "auto",
        "ignoreAutoDns": false,
        "status": "up",
        "autoconnect": true,
        "persistent": true
      }
    ]
  }
}

[coveralls]

coverage: 68.06%. remained the same
when pulling d467382 on encode_connection_id
into bbb2b7d on rc3.

[ancorgs]

We want this included at RC3. So, as I learned, this should be based on (and targeting to) the corresponding rc3 branch.

[teclator]

We want this included at RC3. So, as I learned, this should be based on (and targeting to) the corresponding rc3 branch.

As it was not marked as fastrack I was not sure. I will switch the branch