[Calendar] "Erase all" button for calendar

Discussed in https://github.com/gaborauth/toolsboox-android/discussions/97

^{Originally posted by MairaBelm November 20, 2022} While testing the new Marks calendar feature, I noticed that the Eraser tool works inconsistently, leaving invisible traces or even adding its own traces sometimes. As a result, marks are not always removed after erasing all visible scribbling. Pressing "Update marks" does not make any difference. I am hesitant to open an issue for this because this is probably a Onyx firmware glitch with less effect on other apps that are not relying on scribbling status, but I think an "Erase all scribbles" button or a "Clear marks" one would be a nice addition in case the Eraser keeps misbehaving.