table_panel.libsonnet does not support addOverride

[ywwg]

Many of the panels (e.g. gauge_panel, graph_panel, etc) define addOverride methods. table_panel, however, does not. Could it be added?

[pbrissaud]

Grafonnet still uses the old table panel which is not compatible with Overrides.

[mvh77]

What does this do? https://github.com/grafana/grafonnet-lib/blob/master/grafonnet-7.0/panel/table.libsonnet#L104-L113