[Feature] support aggregate function gauge_agg

[yukkit]

Is your feature request related to a problem? Please describe.

Aggregate gauge data into an intermediate form for use by other functions

• corr
• delta
• idelta_left
• idelta_right
• intercept
• rate
• irate_left
• irate_right
• num_changes
• num_elements
• slope
• time_delta
• gauge_zero_time
• extrapolated_delta
• extrapolated_rate
• interpolated_delta
• interpolated_rate

Describe the solution you'd like

Syntax

--- Returns the aggregated result for a given gauge 'gauge column'
gauge_agg(<time>, <gauge>): <GaugeAgg>

ignore null value

• arguments

time: timestamps associated with each state reading
gauge: the value of the gauge at each point. Support Float64 data type, and all types that can be implicitly converted to Float64.

Describe alternatives you've considered

Additional context

timescaledb
https://docs.timescale.com/api/latest/hyperfunctions/counters-and-gauges/gauge_agg#gauge_agg