Remove outdated qmake pro-files in QtWebSockets and QtWebChannel

Since Qt is built from source using CMake now instead of qmake, the old *.pro files should be removed. This does not include examples and utilities which are not built as part of QtWebSockets and QtWebChannel.

The files to remove from QtWebSockets are:
src/src.pro
src/websockets/websockets.pro
src/imports/imports.pro
src/imports/qmlwebsockets/qmlwebsockets.pro
tests/tests.pro
tests/auto/qml/qmlwebsockets/qmlwebsockets.pro
tests/auto/qml/qml.pro
tests/auto/cmake/cmake.pro
tests/auto/auto.pro
tests/auto/websockets/websockets.pro
tests/auto/websockets/qwebsocketcorsauthenticator/qwebsocketcorsauthenticator.pro
tests/auto/websockets/dataprocessor/dataprocessor.pro
tests/auto/websockets/qwebsocket/qwebsocket.pro
tests/auto/websockets/qwebsocketserver/qwebsocketserver.pro
tests/auto/websockets/handshakerequest/handshakerequest.pro
tests/auto/websockets/websocketprotocol/websocketprotocol.pro
tests/auto/websockets/handshakeresponse/handshakeresponse.pro
tests/auto/websockets/websocketframe/websocketframe.pro
tests/auto/websockets/qdefaultmaskgenerator/qdefaultmaskgenerator.pro

The files to remove from QtWebChannel are:
qtwebchannel.pro
src/src.pro
src/imports/imports.pro
src/imports/webchannel/webchannel.pro
src/webchannel/webchannel.pro
tests/tests.pro
tests/auto/qml/qml.pro
tests/auto/cmake/cmake.pro
tests/auto/auto.pro
tests/auto/webchannel/webchannel.pro