Ramble v0.5.0 release

[linsword13]

This release contains mostly bug fixes and internal improvements. The release notes can be found here.

Features and improvements

• Lazy software environment rendering: Convert environment generation logic to lazy / implcit instead of explicit #433
• Better variable use detection: Implicitly ignore unused variables within experiment definitions #439
• A --simplify workspace command option to prune unused configs: Add command to remove unused configurations #445
• A new ramble deployment command: https://googlecloudplatform.github.io/ramble/workspace.html#workspace-deployments
• Performance improvements on ramble workspace setup: Add caching for define_package_paths step #488, Configure spack install dir based on env_name #495, Ensure consistent spec ordering #504

Removals

• The deprecated default_compiler directive in application definition: Rename default_compiler to define_compiler #428, Merge release v0.5.0 into main #510
• Deprecated spack config sections: Merge release v0.5.0 into main #510