Support for configmaps and secrets in build stages same as pre-cd and post-cd

[dheeth]

Summary

Extend support for configmaps and secrets to be accessible in pre-ci and post-ci stages as it is available in pre-cd and post-cd stages

Motivation

We may need to download some keys or files from private repos or storages, we can store our keys and urls in configmaps and secrets for the same

Proposal

Can be done like pre-cd and post-cd

AB#66