Add support for Obsidian CSS Snippets, "Ignore Folder" settings

[dave-gray101]

This PR includes some useful tweaks I use in my personal Obsidian / Quartz 5 workspace.

• Fixes AssetSyncer - while the code was still around, it seems to have gotten disconnected from Publisher.ts, resolved here. Merged in upstream fix for this issue
• Adds support for Obsidian CSS Snippets
  • Mostly just copies them over, renames *.css --> *.scss to make @use statements work.
  • Converts lucide icons to embedded SVG data url format - allows custom callout icons to work
  • Snippets can be individually toggled on or off in Integration settings if some are not compatible with Quartz at all
• Adds a new setting on Performace settings tab to ignore specific folders and subfolders.
  • Two different UI buttons - top level folders is usually easier to handle and good enough, full subfolder listing available for those who need it
  • Selected folders no longer appear as options in the Publication Center - intended usecases include ignoring a "Templates" folder full of pages with publish: true frontmatter that should not actually ever be published.
• Dataview integration now properly supports .view() including nested scenarios and custom elements.