[Windows] reduce startup time & installation size

Currently Inkscape has thousands of tiny icon and python files. IO hates tiny random reads and makes startup slow.

Some unscientific testing:

HDD:

• Everything: 20 - 25 seconds.
• Every *.png in share/icons except image-missing.png, lib/python folder and bin/python deleted: 8 seconds

SATA SSD:

• Everything: 10-15 seconds
• Every *.png in share/icons except image-missing.png, lib/python folder and bin/python deleted: about twice as fast

So

• Don't include unused png icons. (Ship only svg files?)
• As Inkscape has its own python installation and all packages are vendored by Inkscape to ensure compability, embeddable package and zipimport might yield some improvements by reducing random IO.

Inkscape Version and Operating System:

Version: All?

Windows x64