In this commit, we change the encoding of the sidecar ticket from base68
to base58 as it doesn't contain any special characters which makes copy
pasting a string easier.
An example encoding of the new string looks something like:
```
sidecar13HtPsD1UiB2EA4ZfUbnVejG1Pu3p1GW2ydq65NZBuQgTaD9LRESHtKasXwNrQPYqkwkMyJNFiNoBig4PBQQKoKeXz5jHWXZ3pMZNX5JW2FXyf6zKTPWthRQczNQuf2pM8ppjTqHK6tYTEReZk7pFynYJoHnAeBtix28k2PiRSz5qVVmHpWHWFgVjxihEmcD1T1V1g5LwzVSRUyCJ11ajaE4nHdnU1ZR3HdduxXnyyefacfXWAts3tytr7RnWzRbnVPFSx7eVgeinknYvQ3njtiStpQpSacoBH4y1KckVpRAo8N8KuWWmAgYBNpxZfK8RsgViJ26kTpbfuyyHy1uPkAsGtv25iz5pNcopXyaXMnZGyDDWrDf9ZJEgU6wzm4VxwrPfNN4ASR6wLGWAKy1SsCMVFi5Bx6khN4ReSmJVrALWXrbgM52j7evHVRYXa1LZCJTBccCvaRXNYQqxJvnUnLnHW4N4THv4j1y94wmo2SafRfKapxppVW
```
To allow a ticket to be transported easily over any communication
channel we also provide an easy ascii compatible exchange format which
includes a prefix and a checksum in addition to the tlv stream data.
The string encoding chosen is URL safe base64.
