Add tracing similar to other cosmic apps

[laundmo]

• I have disclosed use of any AI generated code in my commit messages.
  • If you are using an LLM, and do not fully understand the changes it is making to the code base, do not create a PR.
  • In our experience, AI generated code often results in overly complex code that lacks enough context for a proper fix or feature inclusion. This results in considerably longer code reviews. Due to this, AI authored or partially authored PRs may be closed without comment.
• I understand these changes in full and will be able to respond to review comments.
• My change is accurately described in the commit message.
• My contribution is tested and working as described.
• I have read the Developer Certificate of Origin and certify my contribution under its conditions.

I wanted to see if any logs show something about an issue i've been having, but it seems that this project never had logging set up in the first place.

I've looked at other cosmic projects and copied how they tend to set up logs. Specifically, i've taken the setup from cosmic-comp as it seems it doesn't require systemd as a feature flag while also not requiring it at runtime, tho i'm unsure about this.

I've tested it locally, and it seems to work both with cargo run and running through the desktop file after just install

[jackpot51]

It would be good to check if this is portable - what happens when trying to compile this on a non-systemd or non-linux OS?