(fleet) install datadog apm-inject by default

[arbll]

This PR:

• Introduces the install of default packages in the bootstrap process
• Adds some preliminary logic to return datadog-apm-inject:latest when enabled with DD_APM_INSTRUMENTATION_ENABLED
• Adds an override DD_INSTALLER_PACKAGES for tests

[pr-commenter]

Test changes on VM

Use this command from test-infra-definitions to manually test this PR changes on a VM:

inv create-vm --pipeline-id=34805247 --os-family=ubuntu

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 93adc55e-3e3f-4c4d-b884-9c4d45a5b45c
Baseline: 0e8103c
Comparison: 0bdcb2b

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

No significant changes in experiment optimization goals

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

There were no significant changes in experiment optimization goals at this confidence level and effect size tolerance.

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	pycheck_1000_100byte_tags	% cpu utilization	+2.52	[-2.25, +7.30]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+0.52	[-2.37, +3.41]
➖	file_tree	memory utilization	+0.07	[-0.02, +0.17]
➖	trace_agent_msgpack	ingress throughput	-0.00	[-0.00, +0.00]
➖	trace_agent_json	ingress throughput	-0.00	[-0.01, +0.01]
➖	idle	memory utilization	-0.01	[-0.04, +0.03]
➖	uds_dogstatsd_to_api	ingress throughput	-0.01	[-0.21, +0.19]
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.03	[-0.07, +0.02]
➖	otel_to_otel_logs	ingress throughput	-0.10	[-0.47, +0.28]
➖	basic_py_check	% cpu utilization	-1.22	[-3.72, +1.28]
➖	tcp_syslog_to_blackhole	ingress throughput	-9.77	[-29.64, +10.11]

Explanation

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

[codecov]

Codecov Report

Attention: Patch coverage is 81.57895% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 40.60%. Comparing base (0e8103c) to head (0bdcb2b).
Report is 5 commits behind head on main.

❗ Current head 0bdcb2b differs from pull request most recent head fb24ab5

Please upload reports for the commit fb24ab5 to get more accurate results.

Files	Patch %	Lines
cmd/installer/subcommands/installer/command.go	0.00%	13 Missing ⚠️
pkg/fleet/env/env.go	96.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #25677       +/-   ##
===========================================
- Coverage   44.99%   40.60%    -4.40%     
===========================================
  Files        2312       25     -2287     
  Lines      266293     2635   -263658     
===========================================
- Hits       119826     1070   -118756     
+ Misses     136904     1388   -135516     
+ Partials     9563      177     -9386     

Flag	Coverage Δ
amzn_aarch64	40.56% <81.57%> (-5.23%)	⬇️
centos_x86_64	40.56% <81.57%> (-5.14%)	⬇️
ubuntu_aarch64	40.49% <81.57%> (-5.31%)	⬇️
ubuntu_x86_64	40.49% <81.57%> (-5.30%)	⬇️
windows_amd64	19.51% <79.41%> (-31.75%)	⬇️

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[arbll]

Going to merge to fix the e2e tests (tested locally)