internal/golangorgx: delete unused and Go-specific packages

Most of this code does not apply to a CUE LSP at all.
The only bit that might be useful is the logic to fix imports,
but if we need it again it's likely a better idea to look at the
latest code from upstream rather than this old copy.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I917d7bb68f8767d13ebc454164dd290e91536011
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1218447
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Matthew Sackman <[email protected]>

Author: mvdan