Add setting to hide Plotly mode bar

[daniellangnet]

I find that the "mode bar" on Plotly charts can be confusing to people and doesn't add any value in our use of Redash. Hiding it is as simple as adding displayModeBar: false to the Plotly configuration.

I'm happy to submit a PR and make it a setting on the organization ("Hide Plot.ly mode bar"), but before doing so wanted to check if there was support for this idea?

[support]

👋 @daniellangnet, we use the issue tracker exclusively for bug reports and planned work. However, this issue appears to be a support request. Please use our forum to get help.

[arikfr]

@daniellangnet definitely don't mind adding this setting. You're welcome to submit this PR 👍