Move managed fields in YAML tab to metadata

[GuessWhoSamFoo]

What this PR does / why we need it:
Since managed fields are immutable, it does not make sense to show them in the YAML tab which is used to edit objects especially since they take up a lot of space.

They are now moved under metadata:

Which issue(s) this PR fixes

• Fixes ManagedFields optional in YAML tab #2132

Special notes for your reviewer:

A good video to understand purpose of managed fields: https://www.youtube.com/watch?v=P12z8X-qhis

Documentation: https://kubernetes.io/docs/reference/using-api/server-side-apply/

Is there a better way to represent JSON data with current components?

[GuessWhoSamFoo]

We should use https://github.com/josdejong/jsoneditor to show managed fields.

[xtreme-vikram-yadav]

Sorry for bringing this up now but I find black font color taxing on eyes in dark mode and it looks a bit off compared to other text in dark mode. It would be nice if the font color could switch to light in dark mode mode and vice versa.

[mklanjsek]

Nicely done, I like this approach! However new component needs to be styled. In particular: border color, text font and color have to match the rest of the app. Dark theme is especially off with colors. As for font, ideally we should use same fixed font as in Monaco editor.

The way double quotes are escaped is also not ideal, any chance that could be changed?

[GuessWhoSamFoo]

Options that come to mind: raw string literals with backticks, string the output of decoded json byte slice, or fork go. What is a more developer friendly way to do this?