Add custom formatting for latency quantiles for `px live`

[sync-by-unito[bot]]

Our latency quantiles in px live are rendered as a JSON. This is difficult for the user to parse and understand.

For example, px/cluster currently outputs the following in the CLI:

!image-20211210-044427.png|width=1264,height=745!

┆Issue is synchronized with this Jira Bug by Unito ┆Attachments: image-20211210-044427.png