CP-7125 - Make `xl info` easier to use for scripting
Resync with upstream
CP-5759 - Remove power-old hack
Correct URL at the top of the series file
Rather less invasive banner tweaking
Remove the lowmem_emergency_pool unrevert hack.  Its arguments appear incorrect, and implementation doesn't match
CP-7165: backport FIFO-based event channel ABI

Backport all the changesets adding the FIFO-based event channel ABI
and all follow up fixes (include the two not yet applied upstream).

Minor fixups to later patches that also added DOMCTLs were required.