feat: adopt selective dependency packaging (profiles)

[ramonskie]

Summary

Wires the new selective dependency packaging feature into the java-buildpack, adopting the --profile, --exclude, and --include flags introduced in the libbuildpack packager.

Depends on: cloudfoundry/libbuildpack#212

Changes

• manifest.yml — adds packaging_profiles section with two profiles:
  • minimal: JDKs, CF utilities, Tomcat, and common frameworks only (47 → 28 deps)
  • standard: core + open-source APM, OTel, and JDBC drivers (47 → 32 deps)
• scripts/package.sh — parses and forwards --profile, --exclude, --include to buildpack-packager; updates usage()
• README.md — documents selective offline packaging, updated --help output, and expanded package examples
• docs/DEVELOPING.md — documents profile/exclude options in the packaging section
• docs/buildpack-modes.md — adds "Selective Offline Packaging" subsection under Offline Mode

Usage examples

# Full offline build — unchanged behaviour
./scripts/package.sh --cached

# Air-gapped: JDKs + Tomcat only (~28 deps, significantly smaller zip)
./scripts/package.sh --cached --profile minimal

# Ops team: core + open-source observability (~32 deps)
./scripts/package.sh --cached --profile standard

# One-off: drop agents you don't have licences for
./scripts/package.sh --cached --exclude jrebel,your-kit-profiler,jprofiler-profiler

# Minimal profile, but restore jprofiler for a triage build
./scripts/package.sh --cached --profile minimal --include jprofiler-profiler

Notes

• Fully backward compatible: ./scripts/package.sh --cached produces identical output to before.
• --profile, --exclude, and --include are only valid with --cached (enforced by buildpack-packager).
• --include requires --profile to be set (enforced by buildpack-packager).

[ramonskie]

once pr cloudfoundry/libbuildpack#212 is merged.
the CI will create a new pr in each buildpack to update the libbuildpack.

this merge is nesccary before the merge of this pr

[kiril-keranov]

Looks great! Would be very useful