docs: Update mission statement in charter
docs: Update mission statement in charter

... to be consistent with FAQ

Signed-off-by: Matt Wilson <260f5074942ca36dab941199ff6b19fcaa26ccde@amazon.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker