New "Deprecation and Archiving Policy" (#878)
New "Deprecation and Archiving Policy" (#878)

This PR adds a "Deprecation and Archiving Policy" page to the Cordova website.

Its content is the result of this discussion on the mailing list: https://lists.apache.org/thread.html/34369ada22f8a616e90471d38c8fd7def2eb17ff3ddbf4ba0b47987f@%3Cdev.cordova.apache.org%3E

This other PR over in the `cordova-contribute` repository include the steps and notice template required to deprecate a repository: https://github.com/apache/cordova-contribute/pull/2 It refers to the page created in this PR in multiple places.

Please feel free to nitpick any language and grammar problems - I rewrote this quite often, so it is very possible there are some "organically grown" sentences.
purplecabbage/cordova-docs,purplecabbage/cordova-docs,apache/cordova-docs,apache/cordova-docs,purplecabbage/cordova-docs,apache/cordova-docs,apache/cordova-docs,shazron/cordova-docs,shazron/cordova-docs,purplecabbage/cordova-docs,shazron/cordova-docs,shazron/cordova-docs