Flamegraph collector

[Ryado]

Collects a flamegraph representation of trace logs using the system.trace_log table.

Reusing elements from:

• https://github.com/Slach/clickhouse-flamegraph
• https://gist.github.com/alexey-milovidov/92758583dd41c24c360fdb8d6a4da194
• https://github.com/spiermar/d3-flame-graph

TO DO:

• v1 that collects a non-collapsed version in a single file format.
• Enrich the query info by joining with the system.query_log table
• Break down the output to 1 json trace file per query_id
• Create a static HTML query browser that allow to display d3-flame-graph based vizualisations of the queries traces

[Ryado]

v1 is implemented here #68