Add Functional callback to Ticker

[hreintke]

Add Scheduled callback to Ticker
This the rebased version of #4062.

Also adds an example

[devyte]

@hreintke this is supposed to supersede #2738 , but the PR looks broken, e.g.: the source repo seems to be gone.
Could you please take a look? If you make a new PR, please close this one.
You probably know this already, but jic it helps, here's how I do PRs:
-fork this repo to have your own
-clone your fork locally
-make a branch in your local git (e.g.: git checkout -b functicker)
-commit everything to that branch
-push to your fork
-make PR from repo webpage (either your fork or this one)
-If changes are requested, commit to your branch locally, then push to your fork (PR updates automatically)
Once the PR is merged, you can delete your branch.

[hreintke]

@devyte Will check in the coming days.
Need to make sure that I do loose other (local) updates I am using.

[hreintke]

Superseded by #5024