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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[coveralls]

coverage: 100.0%. remained the same
when pulling da28db1 on feature/resolve_overworking_workflows
into 3301e5c on develop.