Add an option to set the file name template for photos / videos

[mkoncek]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

Add a setting where the user can set (or remove) the prefix / suffix for file names of saved photos and videos.

Why do you want this feature?

I want to keep the names of my photos taken from a different phone consistent.

Additional information

Currently I noticed only "Open Camera" application allows something like that.