Easier install on windows from zip through scoop

[boltomli]

To make it easier to install from zip, after installing scoop:

scoop bucket add mywin https://github.com/boltomli/MyWinScripts
scoop install ballerina

I didn't bother to suggest jdk/jre, which most people here should have installed their favourite dist.

[pcnfernando]

looping in @keizer619