Add customized M3 build for Giza

[ColeDCrawford]

• Remove mirador.min.js from base, so it's not loaded on every page
• Add mirador-giza.js build to Giza and import in the allphotos, full, and iiifmanifest templates
• Config is mostly done in the build rather than on the page. miradorInstance is a global set by the build, as is Mirador. miradorInstance needs to be created in advance because of the plugins. See https://github.com/artshumrc/mirador-integration/blob/giza-mirador/src/index.js for details
• Updated scripts in the templates to use config override and Mirador actions / store