[component] Move _fmt_msg() to SoSComponent

[jcastill]

The function _fmt_msg() was in three different subsystems. This commit removes the code from collector, cleaner, and upload into SosComponent.

Related: #3746

---

Please place an 'X' inside each '[]' to confirm you adhere to our Contributor Guidelines

• Is the commit message split over multiple lines and hard-wrapped at 72 characters?
• Is the subject and message clear and concise?
• Does the subject start with [plugin_name] if submitting a plugin patch or a [section_name] if part of the core sosreport code?
• Does the commit contain a Signed-off-by: First Lastname [email protected]?
• Are any related Issues or existing PRs properly referenced via a Closes (Issue) or Resolved (PR) line?
• Are all passwords or private data gathered by this PR obfuscated?

[jcastill]

This commit was originally part of the upload PR, 3746, but I dropped it to focus on only the upload subsystem.
I didn't see any PR for this already, so I went ahead with it. If anybody else prefers to work on it, feel free to close this and apologies for the extra work.

[packit-as-a-service]

Congratulations! One of the builds has completed. 🍾

You can install the built RPMs by following these steps:

• sudo yum install -y dnf-plugins-core on RHEL 8
• sudo dnf install -y dnf-plugins-core on Fedora
• dnf copr enable packit/sosreport-sos-3938
• And now you can install the packages.

Please note that the RPMs should be used only in a testing environment.