Added link to the portable Windows zip on Sourceforce ([NEST-31](https://issues.imfreedom.org/issue/NEST-31))

Added link to the portable Windows zip on Sourceforce NEST-31
Also added a single line to describe Finch NEST-30

Testing Done:
Firefox 80.0.1 (64-bit)

Bugs closed: NEST-30, NEST-31

Reviewed at https://reviews.imfreedom.org/r/133/