[Priority-low] Add file manager icon variants

[keeferrourke]

Some people would prefer their file manager icons not to have faces. It is planned to add variants for file manager icons that are drawn in a similar style, but without the "Finder" face. It should be easy for users to choose their preferred style in configure by following a prompt.

The current style icons will likely remain the default, however possible variants may include:

• simplified version of existing icon with the face and some decals removed
• a redesigned file manager icon more similar to the default GNOME theme
• a more Material inspired file icon, similar to Amaze
• a more macOS style icon, that is more similar to Finder than the existing style in v0.3.0

This gives the user more choice in how their system looks and feels, through providing a spectrum of options.

This change was initially requested on Github in #33, and a few times on GNOME-Look.

[fcole90]

👍

[keeferrourke]

Work toward the completion of this issue has been indirectly started as I try to complete theming for various wine applications. winefile.svg provides a Windows Explorer style icon.

Once other variants are added, I'll add the option to customize the file manager icons via the ./configure script.

[sh4nks]

@keeferrourke any updates on this issue?