This adds a new helper which retrieves the build metadata, uses it to generate container labels, and refactors XFlags uses to utilize the same machinery.
Co-authored-by: James Elliott <james-d-elliott@users.noreply.github.com>
This commit adjusts the build flags to include version information in the LDFLAGS using the -X options. Additionally this makes the information recorded at build time more comprehensive. All build information can now be obtained via the `authelia build` command, and the `authelia version` command is now `authelia --version`. Lastly this adjusts the Dockerfile to utilize docker cache more effectively.