Editor: Remember text settings

[gimplyworxs]

Description of requested feature:

It would be nice if shutter remembered the text settings when editing a screenshot.
At the moment I have to set the font and size for each single text field I create.
Not very comfortable. Shutter can remember the colours of text well, so why not font and size?

Reasons for adding feature:

Extra information, such as Shutter version, operating system and ideas for how to implement:

Shutter version 0.99.2 on Linux Mint 20.1 MATE

[Photon89]

I think, this is related to #301.