Nexus: Add securityContext to jobs

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/apps/developer-tools/nexus/-/blob/45.0.0-bb.2/CHANGELOG.md

Package MR

https://repo1.dso.mil/big-bang/apps/developer-tools/nexus/-/merge_requests/77

For Issue

Closes https://repo1.dso.mil/big-bang/apps/developer-tools/nexus/-/issues/51