* Publish project of SPARK examples
This will be useful for training / tutorials based on Alire.
* Updated the examples to include drivers for execution
Also applied the rest of transformations described in alire#227: no top-level
[genera] table, name/version keys, [[depends-on]] array instead of table.
Crates without maintainer or pending migration remain in /orphaned
GitHub URLs rely on the default tarballs that at some point will
have to be released with uploaded binaries (with `alr publish` support).