Add granular Apple build primitives

Fabrik now supports TOML-declared Apple Swift build primitives for apple.swift_library, apple.static_framework, apple.dynamic_framework, and apple.macos_command_line_application. swift_library targets expand into separate cacheable compile and archive actions, and library, executable, and framework actions correctly depend on the appropriate outputs from their dependencies. Dependencies within the same fabrik.toml file can be written by target name, and relative paths using ./ and ../ resolve from the declaring fabrik.toml, making Apple projects easier to declare and build with finer-grained, reusable actions.