[GR-42693] First draft of native-image bundle support.

[graalvmbot]

This PR adds basic bundle support. Two new options are added:

    --bundle-create[=new-bundle.nib]
                          in addition to image building, create a native image bundle file (*.nib
                          file) that allows rebuilding of that image again at a later point. If a
                          bundle-file gets passed the bundle will be created with the given name.
                          Otherwise, the bundle-file name is derived from the image name. Note
                          both bundle options can be combined with --dry-run to only perform the
                          bundle operations without any actual image building.
    --bundle-apply=some-bundle.nib
                          an image will be built from the given bundle file with the exact same
                          arguments and files that have been passed to native-image originally
                          to create the bundle. Note that if an extra --bundle-create gets passed
                          after --bundle-apply, a new bundle will be written based on the given
                          bundle args plus any additional arguments that haven been passed
                          afterwards. For example:
                          > native-image --bundle-apply=app.nib --bundle-create=app_dbg.nib -g
                          creates a new bundle app_dbg.nib based on the given app.nib bundle.
                          Both bundles are the same except the new one also uses the -g option.

1. Create a new bundle with --bundle-create:

> native-image --bundle-create=simple-bundle.nib -cp cp HelloJava

This creates a new bundle that contains the all files from the cp directory and captures the command line args used to create the bundle (-cp cp HelloJava) and all files that were created during image building. Those files are also directly available in directory simple-bundle.output next to the bundle. It is also possible to just create the bundle without getting the image built as well. When --bundle-create is combined with --dry-run a bundle will be created that does not contain an image and also no <bundlename>.output gets created. This is useful if you just want to create a bundle on a machine but build an image from that bundle somewhere else (maybe on a more powerful machine i.e. a build server).

If no filename is passed to --bundle-create then the name of the bundle will be derived from the image name. E.g. in the above case omitting =simple-bundle.nib would result in a bundle named hellojava.nib (because the image name is derived form the main class name HelloJava).

A common pattern that I expect to emerge is users to inject --bundle-create to non-trivial maven or grade native-image builds to retrieve a bundle. For example, adding graalvmNative { binaries { main { buildArgs.add('--bundle-create') }}} in build.gradle of a spring-boot-native application will produce a bundle that can later be rebuilt without requiring the original project. The bundle alone is self-contained and contains everything needed to build the application again.

2. Build an image again from a bundle with --bundle-apply:

native-image --bundle-apply=simple-bundle.nib

The image will be rebuilt in the simple-bundle.output directory.

Note that passing any additional arguments after --bundle-apply will be taken into account in the image build. For example:

native-image --bundle-apply=simple-bundle.nib --pgo-instrument

will again create directory simple-bundle.output but this time the image is built with arguments -cp cp HelloJava --pgo-instrument.

3. Creating a new bundle from an existing one with --bundle-apply + --bundle-create:

Suppose you have a bundle and you want to derive another bundle from it that builds the original application but with pgo optimization. This can be achieved by combining --bundle-apply with as subsequent --bundle-create. For example if we have pgo profile information in the form of a default.iprof in our current working directory we could use the following command to create a new bundle that can build a pgo optimized image.

native-image --dry-run --bundle-apply=simple-bundle.nib --pgo --bundle-create=simple-bundle-pgo.nib

The newly created bundle will contain the default.iprof and the arguments needed to pass it to the builder. Also note the use of --dry-run here again. This will skip image building and only create the new bundle.