Have 'Metadata' place in trace server provider

[MatthewKhouzam]

It would be interesting to get trace specific one shot data,

e.g. :

• Host Name
• CPU architecture (number of cores/bigLITTLE?)
• System Memory
• GPUs available (number of compute cores?)
• Network config
• Storage config
• Program being traced, if known
• Anything immutable on a given trace (on older systems, frequency)

This information can help with Axes ranges as well as giving more context to the user.