misc: drop remnants of the old and now-unused web chatview

src/app/messagesadapter.h

src/libclient/CMakeLists.txt

src/libclient/api/chatview.h

src/libclient/chatview.cpp

src/libclient/web-chatview/chatview-gnome.css

src/libclient/web-chatview/chatview-qt.css

src/libclient/web-chatview/chatview.css

src/libclient/web-chatview/chatview.html

src/libclient/web-chatview/chatview.js

src/libclient/web-chatview/emoji.css

src/libclient/web-chatview/emoji.js

src/libclient/web-chatview/fa.css

src/libclient/web-chatview/jed.js

src/libclient/web-chatview/linkify-html.js

src/libclient/web-chatview/web.gresource.xml

src/libclient/webresource.qrc