enable to output `verify-resource` result in JSON/YAML format

[hirokuni-kitahara]

Signed-off-by: Hirokuni-Kitahara1 hirokuni.kitahara1@ibm.com

this PR is for the issue: https://github.com/sigstore/k8s-manifest-sigstore/issues/8

• add output option to verify-resource command and enable to output verify-resource result in JSON/YAML format
• minimize the number of image pulls using on memory cache only in verify-resource