[Plots] Allow Plot views to toggle axis grid lines visibility

[charlesh88]

Overview

Allow the user to toggle the axis grid line visibility of a given plot view.

Expected Behavior

• When displaying gridlines, clicking toggle button should hide gridlines and change toggle button icon accordingly.
• When not displaying gridlines, clicking toggle button should show gridlines and change toggle button icon accordingly.

Steps to Reproduce

1. Navigate to a telemetry endpoint
2. [Verification] Verify toggle gridlines button is available in both view only and edit mode
3. [Verification] Verify you can toggle gridlines by clicking the button
4. Repeat verification steps using an overlay plot
5. Repeat verification steps using a stacked plot
6. Repeat verification steps within a display layout (layout object must be large enough to enable buttons)
7. Repeat verification steps when previewing plot (edit an object and click on a plot to preview)

Design Notes

• I think this should be a persistable property of the view, rather than a real-time usage gesture. Showing or hiding axis gridlines has to do with information density, noise reduction and informational clarity - all of which relate to the work involved when composing a view.
• In stacked plots, the setting would be global and would apply to all child plot views, including other composed plot views that may have their own independent setting.
• For extra credit, we could make horizontal and vertical axis lines separately settable.

[shefalijoshi]

@davetsay @charlesh88 Has this issue been satisfied by the accompanying PR? If so, should it be marked closed/unverified?