Add host ID reporting to application metrics

[mariomac]

This patch:

1. Fetches host ID from the major cloud providers APIs.
2. If (1) fails, tries to get the Kubernetes Node machineID
3. If (2) fails, tries to get the /etc/machine-id
4. if (3) fails, fallbacks to the host name

It also adds the target_info metric report to the Prometheus exporter, as there is required as standard way of reporting the host ID. This metric will be active when the prometheus exporter is active for any of the application metrics subgroup, and can't be disabled.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 66.66667% with 37 lines in your changes missing coverage. Please review.

Project coverage is 81.36%. Comparing base (c8e6a58) to head (34551ef).
Report is 104 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/internal/pipe/global/host_id.go	52.05%	34 Missing and 1 partial ⚠️
pkg/internal/kube/informer_provider.go	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1042      +/-   ##
==========================================
- Coverage   81.46%   81.36%   -0.10%     
==========================================
  Files         138      139       +1     
  Lines       10988    11073      +85     
==========================================
+ Hits         8951     9010      +59     
- Misses       1521     1549      +28     
+ Partials      516      514       -2     

Flag	Coverage Δ
integration-test	56.08% <54.95%> (-0.01%)	⬇️
k8s-integration-test	58.94% <58.55%> (-0.04%)	⬇️
oats-test	37.24% <39.63%> (+0.01%)	⬆️
unittests	51.09% <57.65%> (+0.10%)	⬆️

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[grcevski]

LGTM! Really awesome work!