Integrate code coverage into Travis pipeline and GitHub PR workflow

[fearphage]

This is a follow-up to #6875. Related to d481172.

Now that coverage exists, we need to upload the results to a service that will track the coverage over time and that integrates with GitHub to share the progress in the pull requests.

The 2 I most commonly come across are:

• https://coveralls.io/
• https://about.codecov.io

Both have integrations and examples showing how to integrate into your current Travis workflow. Here are links to the related maven plugins:

• Coveralls plugin / example PR output.

• CodeCov plugin for Jacoco / example PR output

I believe the first step is to setup an account with one of the selected services. I can do the work of adding the plugins and such, but an admin would need to setup the project in Coveralls or CodeCov and supply any API keys or related artifacts.

[JayDi85]

As I stated in d481172 -- coverage report can't be enabled in CI process due project size. It takes almost 1 hour on good computer to generate and upload full report to the sonar (on 2023 it takes 10+ hours on default report).

Example: my computer runs tests 2-3 minutes compared to 10 minutes on current travis's CI (coverage + sonar takes 30-60 mins) -- so full coverage report must takes few hours in CI.

Maybe there are possible other way, don't known.

Sonar cloud's track coverage report:
https://sonarcloud.io/dashboard?id=JayDi85_mage

[JayDi85]

You can test integration with local or forked repository. If it works fine then it will be added to current.

[JayDi85]

Actual static code analysis report by sonarcloud available from that url: https://sonarcloud.io/project/overview?id=magefree_mage or from badges in readme/main github's page.

It also contains a code coverage report by jacoco. I'll updates it manually time by time (once per week/month/etc).

Sonarcloud takes 6+ hours to process whole project on good PC, so it can't be integrated on cloud hosting CI like travis or github actions.

[JayDi85]

Current workflow for manual build and analysis (run by maven):

1. Clean and build project:

mvn clean install -DskipTests

2. Run tests with code coverage report:

mvn install -Djacoco.skip=false -Dmaven.test.failure.ignore=true

3. Run sonarcloud analysis (replace org, project and token by your own):

mvn -e sonar:sonar -Dsonar.projectKey=magefree_mage -Dsonar.organization=magefree -Dsonar.host.url=https://sonarcloud.io -Dsonar.token=SONAR_ACCESS_HERE