- #859 added the traversal necessary to load the app bundle but forgot
to resolve symlinks. This fix adds the resolution, making it possible to
get default system properties from an app bundle Info.plist even if the
user invokes a command from, for example, `/usr/local/bin/container`
which is a symlink to the actual install path of the bundle.
- Also fixes bugs where an incorrect executable path was supplied in
some calls.
- Breaking change: `CommandLine.executablePathUrl` extension moved from
ContainerPlugin to ContainerVersion.
- Sets up API server as source of truth for installation root, similarly
to what was done for the data root. `system start` establishes the
install root, setting the environment variable `CONTAINER_INSTALL_ROOT`
when launching the API server.
- The API server propagates the environment variable when launching
helpers, and returns the install root to the CLI via the health check
XPC.
- Includes several fixes for detecting plugins that use app bundle
layout.