Special version for Plasma 5.19+

I got a few reports pointing to the fact that in Plasma 5.19, Webslice would crash everything. The cause was somewhat simple, as some QML packages (WebKit) were deprecated.
But, doing the conversion to WebView meant that a few features don't work anymore, notably, the customized context menu, the middle click or ctrl+click to open links in an external browser, or just having the load indicator.
That's why this release is separated from the others.

Eventually, I'll rebuild the whole plasmoid to use WebEngineView, which would allow better extensibility, but that's for the futur.

So, use this only if Webslice crashes for you.