Resolve "BigBang support for GitLab SMTP Password Secret"

BigBang Merge Request

Use BigBang templating to create a secret for Gitalb smtp password. The secret name value is also passed through to the Gitlab Package chart.

Package MR

no package MR needed

For Issue

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/1139