Feature: Option for alternative (more readable) filename patterns

[RustoMCSpit]

Feature Request

Right now, my recordings are saved as e.g. 2023_12_22_20_46_18.m4a, but I would like them to be saved as something like:

2023-12-22_204618.m4a
20231222_204618.m4a or
2023-12-22_20-46-18.m4a

The reason is because it's easier to visually (and programmatically) distinguish the date from the time. Android saves camera photos as IMG_20231210_051153_297.jpg by the way.

I guess one could either implement a set of formats to choose from, or a field where one could enter a custom pattern like Markor does; it provides an option where one can enter a pattern for SimpleDateFormat (in case this is already used by Simple Voice Recorder, idk).

FossifyOrg/Voice-Recorder#15