WIP: Feat: Add support for shex imports to @ldo/cli

[mrkvon]

Work in progress.

• import shex from other file
• nested dependencies
• circular dependencies
• import from web
• clean up and refactor

Issues to address:

• do not use absolute IRIs (paths) for local files. That's not transferrable to other filesystems and leaks information about person's filesystem.
• typings should be imported as import type, but dts-dom doesn't seem to support that. Maybe we can run linter to fix this (fixable issue).
• cosmetic: import { Type as Type } from "./somewhere" could become import { Type } when they match.
• don't export from shapeType what's not defined in the shape itself.
• contexts need to be merged in some way. We need to be careful about term overlap (like schema:name vs foaf:name etc.)
  • Best would be nested contexts, but LDO dataset-proxy's nested context only seems to work 1 level deep
  • Alternative would be to make sure names are deduplicated across the import graph.
• Currently only imports where imported schema appears as object within other schema. (Only that is tested). Generalize?