Added paths filter to regulate workflow executions

[fktn-k]

This PR has added some filters of triggering workflows depending on what kind of files have been changed.
For, previously, all the workflows were activated on every commit regardless of what kind of changes have been made, which forces developers (especially me) to wait for an unnecessary amount of time, for example, modifying only the README file activates the Valgrind check.
So, after merging this PR, commits on main/develop or other branches for PRs will activate the minimum required workflows.

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• [x] Changes are described in the pull request or in a referenced issue.
• [x] The test suite compiles and runs without any error.
• [x] The code coverage on your branch is 100%.
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[coveralls]

coverage: 100.0%. remained the same when pulling da28db13ee55929bf816bd297e472417d99cf4d8 on feature/resolve_overworking_workflows into 3301e5c2371b3337313729fd99c7447e255ec9ab on develop.