Improved CI jobs logs and error handling

[adrienbernede]

Summary

This ports the GitLab CI log-folding improvements from llnl/Umpire#1049 to Caliper's GitLab build script.

The goal is to make CI logs easier to navigate without changing the underlying build/test workflow.

What changed

• add reusable helpers for GitLab collapsible sections
• add portable UTC timestamps and elapsed-time reporting
• add nested section support for clearer CI log structure
• redirect stderr to stdout so section output stays grouped in CI logs
• replace ad hoc timing messages with structured foldable sections
• improve error/info/warning output for failed CI steps
• preserve command exit status when piping ctest output through tee
• use safer host-config discovery with nullglob

Project-specific notes

This keeps the existing Caliper behavior intact, including its project-specific build, test, and cleanup logic. Only the CI log structure and related error/reporting flow were updated.

Why

Large GitLab logs are difficult to inspect when everything is printed as a flat stream. Foldable sections make it much easier to:

• jump to the relevant phase
• spot failures quickly
• understand where time is spent in CI

Testing

• bash -n scripts/gitlab/build-and-test.sh