Deprecate form-field standard and legacy appearance

[devversion]

For V11, we should deprecate the standard and legacy form-field appearances. We already did it in the past, but reverted immediately as the filled/outlined appearances were not having good prefix/suffix icon alignment.

We decided that we just want to fix this as part of our MDC effort. As the spec, and MDC do not support these legacy/standard
appearances anymore, we need to deprecate the appearances. This is slated for v11 and this issue is primarily for tracking.

[crisbeto]

Closing since this is done.

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