Add initial bridgetown template for Pages

.gitignore

.ruby-version

Gemfile

Gemfile.lock

README.md

Rakefile

bin/bridgetown

bin/bt

bridgetown.config.yml

config.ru

config/esbuild.defaults.js

config/puma.rb

esbuild.config.js

frontend/javascript/index.js

frontend/styles/index.css

frontend/styles/syntax-highlighting.css

package.json

plugins/builders/.keep

plugins/site_builder.rb

postcss.config.js