Enable bypassing the assets generator

[seanaery]

It'd be really valuable to add a --skip-assets option to the InstallGenerator. This option exists in Blacklight core, and I have found it essential in cases where my application's Javascript approach doesn't quite match the assumptions made by the generator and needs more nuanced/manual setup (e.g., applications that are still using Sprockets for JS).

E.g., currently if running generate 'blacklight_range_limit:install' in a Blacklight 8 application that began with generate 'blacklight:install', '--skip-assets' & generate 'blacklight:assets:sprockets' I get this error, as I have neither importmap-rails nor package.json.

info  =================================
        info  Installing Blacklight Range Limit
        info  =================================
    generate  blacklight_range_limit:install
       rails  generate blacklight_range_limit:install 
    generate  blacklight_range_limit:assets
       rails  generate blacklight_range_limit:assets 
/gems/ruby/3.3.0/gems/blacklight_range_limit-9.0.0.beta1/lib/generators/blacklight_range_limit/assets_generator.rb:37:in `set_default_options': Could not identify asset_delivery_mode, try supplying --asset-delivery-mode=[importmap-rails|yarn-package] (ArgumentError)

          raise ArgumentError.new("Could not identify asset_delivery_mode, try supplying --asset-delivery-mode=[importmap-rails|yarn-package]")

[jrochkind]

Yes, we need this. Also for people installing in situations that work but our installers can't do automatically, like vite_rails.

I'll try to get to it, although suddenly got kind of overwhelmed with tasks today!