chore: bring back stand-alone agent

[mdelapenya]

• chore: apply functional opts to agent deployment
• chore: rename deployment method
• chore: simplify stand-alone deployment removing flavour
• fix: revoke token scenario was outdated
• chore: simplify deploy stand-alone agent method
• chore: skip scenario for bootstrap fleet server agent in stand-alone
• chore: include stand-alone agent in CI

What does this PR do?

It adds the stand-alone agent scenarios to the CI including a few changes:

• the bootstrap fleet-server scenario is skipped, because it uses docker-compose to start the fleet-server in local, and the agent is using the already deployed stack
• uses a new functional approach (more Go idiomatic) when deploying an agent to Fleet. It uses optional functions instead of input parameters to configure the deployment (installer type, extra flags, etc)
• updates the revoke-token scenario, as it was based on the old docker-compose style. Now it installs the agent, revokes the token, uninstalls it, and tries to install an agent with the same token again
• detected that Ansible Docker ARM role was not applied to the ARM instances, causing a failure for having Docker not installed on the instance. Docker is needed because the stand-alone mode uses the Docker image of the elastic-agent.

Why is it important?

Add scenarios that were already working in the past, also improving the readability of the deploment of the agent code

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have run the Unit tests (make unit-test), and they are passing locally
• I have run the End-2-End tests for the suite I'm working on, and they are passing locally
• I have noticed new Go dependencies (run make notice in the proper directory)

Related issues

• Relates [Fleet] Add support & test for passing in api token to Docker container to move a stand-alone Agent to be Fleet enrolled #541

[elasticmachine]

💔 Tests Failed

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Build stats

• Start Time: 2022-08-01T15:17:29.065+0000

• Duration: 68 min 12 sec

Test stats 🧪

Test	Results
Failed	1
Passed	417
Skipped	0
Total	418

Test errors

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Initializing / End-To-End Tests / fleet_debian_10_arm64_system_integration / Adding cpu system/metrics Integration to a Policy – System Integration

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 Step "system/metrics" with "cpu" metrics are present in the datastreams 

• no stacktrace

Steps errors

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Start Elastic Stack

• Took 10 min 28 sec . View more details here
• Description: make -C .ci start-elastic-stack

generate-cucumber-reports.sh

• Took 0 min 0 sec . View more details here
• Description: .ci/scripts/generate-cucumber-reports.sh

Run tests in the node

• Took 27 min 57 sec . View more details here
• Description: make -C .ci run-tests

🐛 Flaky test report

❕ There are test failures but not known flaky tests.

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Genuine test errors

💔 There are test failures but not known flaky tests, most likely a genuine test failure.

• Name: Initializing / End-To-End Tests / fleet_debian_10_arm64_system_integration / Adding cpu system/metrics Integration to a Policy – System Integration

🤖 GitHub comments

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[mdelapenya]

Mmm the Ansible role to install Docker does not install Docker Compose on ARM. Will take a look, as it's an external dependency