Replace use of `LegacyForm` in UI components

[jorge0136]

I have been working through the excellent Build a Datasource Plugin tutorial. One thing that I have found confusing is the use of the LegacyForm in the react components used in the tutorial. I am seeing these used in two places:

• QueryEditor
• ConfigEditor

I have wanted to extend my forms to be more complex but I have been unable to find any documentation for how the LegacyForms are supposed to be used. I have found excellent documentation about the next generation of the UI components. ~I am assuming that an update to something more like what we see used in the VariableQueryEditor of the Add support for variables tutorial would be the right thing to do here.~ I think I could replicate much of what is found in this QueryEditor.

Is there any context that I am missing around the use of the LegacyForms here? Would a PR with updates be welcome?

Thanks for the tutorials and the project generator, they have both been super helpful. :)