Rename build.json to bmeta.json
Rename build.json to bmeta.json

In order to consolidate the names of the various JSON files involved,
rename build.json to bmeta.json as this is for the kernel build
meta-data.  The same name is used by `kci_build build_kernel` and then
`kci_build install_kernel`.

Signed-off-by: Guillaume Tucker <e7e20b7c30f19d4ca6b81319ef81bf200369d137@collabora.com>

kernelci/kernelci-backend,kernelci/kernelci-backend