Refactor packages to have more idiomatic code base

api/category.go

api/controller.go

api/entry.go

api/feed.go

api/icon.go

api/payload.go

api/subscription.go

api/user.go

cli/cli.go

cli/create_admin.go

cli/flush_sessions.go

cli/info.go

daemon/daemon.go

daemon/routes.go

daemon/server.go

fever/fever.go

filter/image_proxy_filter.go

filter/image_proxy_filter_test.go

generate.go

http/cookie/cookie.go