Convert cue import into typescript

[ying-jeanne]

an example of cue import https://github.com/grafana/grafana/blob/main/public/app/plugins/panel/timeseries/models.cue

[ying-jeanne]

an example would be something in cue:

import (
    ui "github.com/grafana/grafana/packages/grafana-schema/src/schema"
)

to

import * as ui from "@grafana/ui"

[sdboyer]

What we want here is, i think, an entirely separate generator from our existing func Generate(), on the expectation that we're going to want to handle import generation separately from generating the body. This is a necessary outgrowth of our existing type signatures - if we want Generate() to continue taking a cue.Value (and we do), then swimming back upstream from the cue.Value to finding import statements becomes difficult, so we should handle them separately.

This would be a reasonable signature:

type ImportMapper func(*ast.ImportSpec) (string, error) // Already in cuetsy, but needs type sig change
func GenerateImports(imports []*ast.ImportSpec, mapper ImportMapper) ([]byte, error) {}

We could, at some later point, add an e.g. func GenerateFile(), which itself would internally call GenerateImports() and Generate(), but for now we can leave it up to the user to put these bits together themselves.