Remove CI_BUILD_* predefined variables

Remove the following variables from our code base

Removed variable	Replacement variable
CI_BUILD_BEFORE_SHA	CI_COMMIT_BEFORE_SHA
CI_BUILD_ID	CI_JOB_ID
CI_BUILD_MANUAL	CI_JOB_MANUAL
CI_BUILD_NAME	CI_JOB_NAME
CI_BUILD_REF	CI_COMMIT_SHA
CI_BUILD_REF_NAME	CI_COMMIT_REF_NAME
CI_BUILD_REF_SLUG	CI_COMMIT_REF_SLUG
CI_BUILD_REPO	CI_REPOSITORY_URL
CI_BUILD_STAGE	CI_JOB_STAGE
CI_BUILD_TAG	CI_COMMIT_TAG
CI_BUILD_TOKEN	CI_JOB_TOKEN
CI_BUILD_TRIGGERED	CI_PIPELINE_TRIGGERED

Link to the deprecation announcement