Was borked on linux if you didn't provide the setting in `conf.toml` due
to some logic errors. Fix that by rejigging `DpiAwareFont` internal
variables:
- add new `._font_size_calc_key: str` which was the old `._font_size`
and is only used when no explicit font size is set by the user in the
`conf.toml` config:
- this is the "key" that is used to lookup a calculation function
which attempts to compute a best fit font size given the measured
system displays DPI settings and dimensions.
- make the `._font_size: int` the **actual** font size integer that is
cached and passed to `Qt` to set the size.
- this is overridden by user config now if defined.
- change the input kwarg `font_size: str` to the constructor to better
change the input kwarg `font_size: str` to the constructor to better
named private `_font_size_key: str` which gets set to the new
`._font_size_calc_key`.
Also, adjust all client code which instantiates `DpiAwareFont` to use
the new `_font_size_key` kwarg input so nothing breaks XD
Tyler Goodlet