Port to BuildStream 2
This uses the abderrahim/bst2-22.08
branch from freedesktop-sdk, which is a port of 22.08 to buildstream 2. Porting directly to freedesktop-sdk master requires some effort around compatibility with newer versions that I'd rather avoid at this point to avoid making this MR bigger. This means that the ABI break would be a bit later in the cycle.
Edited by Abderrahim Kitouni