feat(ids): Support custom IDs for Sketch library sync

[macintoshhelper]

This adds a document/page name option in the config together with a customIds opt-in option that uses permanent IDs for shared styles in html-sketchapp if you know all IDs (data-sketch-text) are unique and will not change.

This PR should fix library sync between updates (symbols can have a permanent ID).

Documentation should probably be added to the README.md for setting symbol IDs:

  symbolMiddleware: ({ symbol, node, suffix }) => {
    const symbolName = node.dataset.sketchSymbol;

    symbol.setId(`${symbolName}${suffix}`);
    symbol.setName(symbolName);
  },

New config options:

{
  name: 'project-id-here',
  customIds: true
}

Depends on changes in html-sketchapp/html-sketchapp#151 (that would need to be merged first).

#18

[macintoshhelper]

symbol-middleware.test.js fails because of a snapshot test mismatch. Not sure what's causing this and whether it's safe to override the snapshot test.

[markdalgleish]

Hey, thanks for this PR! Definitely keen to support this behaviour. However, since we're unable to merge this PR until html-sketchapp/html-sketchapp#151 is merged first, I'm closing this for now. Please feel free to reopen once this is no longer the case.

[michalsnik]

The html-sketchapp/html-sketchapp#151 has been merged, can you please reopen this PR @macintoshhelper @markdalgleish ? :)

[macintoshhelper]

I've reopened it with changes for the new text middleware, apologies for the delay!

@michalsnik @markdalgleish