This commit implements issue #327 by adding dyes and microscopes to the
comprehensive Algolia search bar.

Backend changes:
- Added DyeIndex and MicroscopeIndex to proteins/index.py
- Added url property to Dye model (links to spectra viewer)
- Added url and owner_name properties to Microscope model
- Updated base.html template to expose dyeIndex and microscopeIndex

Frontend changes:
- Updated algolia.js to initialize dye and microscope indices
- Added autocomplete sources for dyes (3 per page) and microscopes (2 per page)
- Updated highlightHits to support manufacturer, part, slug, and owner_name fields
- Added placeholder icon images for dye and microscope results

Dyes link to the spectra viewer (/spectra/<slug>) and microscopes link to
the microscope detail page (/microscope/<id>/).

Note: Algolia indices need to be populated using Django management commands:
  python manage.py algolia_reindex --model Dye
  python manage.py algolia_reindex --model Microscope