metrics baseline in compute-baseline.json

metrics baseline in compute-baseline.json

- Previously, metrics baseline are defined in the spec file.
In this patch, move metrics baseline to compute-baseline.json.
- you can get qpi based with baseline file given in calculate.yml
- you can generate a customized baseline file when baseline file is
not given in calculate.yml

And baseline will be removed from the spec file.

Change-Id: I123d28e28543cb153b60120b5076306fa2fa3873
Signed-off-by: zhihui wu <wu.zhihui1@zte.com.cn>