Use default value when -otelconfig option not given

[adam-mateen]

Description of the issue

The problem is some users directly start the amazon-cloudwatch-agent program.
Until recently there was no -otelconfig option.
Now there is, and it is breaking some users (missing metrics).

Description of changes

Most of the changes are refactoring some common code from start-amazon-cloudwatch-agent into tools/paths package. Ultimately I just want to reuse the same variable the start-amazon-cloudwatch-agent program uses when it generates the YAML config.

License

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Tests

• make build, make test
• Manually copied the linux_amd64 binaries to a test host and started the agent with the default linux config.

Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

[codecov-commenter]

Codecov Report

Attention: 37 lines in your changes are missing coverage. Please review.

Comparison is base (96d4763) 57.58% compared to head (2d697a2) 62.41%.
Report is 419 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #894      +/-   ##
==========================================
+ Coverage   57.58%   62.41%   +4.82%     
==========================================
  Files         370      339      -31     
  Lines       17548    17106     -442     
==========================================
+ Hits        10105    10676     +571     
+ Misses       6848     5877     -971     
+ Partials      595      553      -42     

Files	Coverage Δ
cfg/commonconfig/commonconfig.go	8.00% <ø> (ø)
...md/amazon-cloudwatch-agent-config-wizard/wizard.go	59.55% <ø> (-8.51%)	⬇️
...amazon-cloudwatch-agent/amazon-cloudwatch-agent.go	2.64% <ø> (ø)
...oudwatch-agent/register_event_logger_notwindows.go	0.00% <ø> (ø)
...-cloudwatch-agent/register_event_logger_windows.go	0.00% <ø> (ø)
cmd/config-translator/translator.go	0.00% <ø> (ø)
cmd/xray-migration/commands_unix.go	42.50% <ø> (ø)
cmd/xray-migration/commands_windows.go	42.50% <ø> (ø)
cmd/xray-migration/xray-migration.go	30.28% <ø> (ø)
handlers/agentinfo/info.go	84.94% <ø> (ø)
... and 22 more

... and 206 files with indirect coverage changes

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