fix(windows): implementation structure

[janpio]

The Windows implementation was in a strange location in www, moved it to src like all the other platform implementations.

Also removes the wp platform and fixes tiny things in plugin.xml and package.json.

TODO:

• Check if this is a breaking change or can be done in a minor update.

[timbru31]

LGTM 👍 - also the breaking change was done in #143, so IHMO this is a patch/minor release since you just cleaned-up some forgotten files.

[janpio]

The "breaking" comment mainly referred to the moving of www/windows/SplashScreenProxy.js to src/windows/SplashScreenProxy.js. At first I was not sure if anythign external could rely on the file being in this location.

What do you refer to in #143?

[timbru31]

The "breaking" comment mainly referred to the moving of www/windows/SplashScreenProxy.js to src/windows/SplashScreenProxy.js. At first I was not sure if anythign external could rely on the file being in this location.

I personally doubt that anything external relies on this. At least not in a supported/intended way (of course you can always manually modify files in the your node_modules/platforms folder...)

What do you refer to in #143?

I referred to the removal of the wp8 platform

[erisu]

I cleaned up this PR to be focused on the single original goal by splitting out other changes.

This PR now LGTM 👍

I will merge this in after the CI service finishes running.