Bug#963725: fcitx5: Lack of proper metapackages/instructions / not work out-of-the-box

[Yangfl <mmyangfl@gmail.com>]

Source: fcitx5

Dear Maintainer,

In the current packaging scheme, most people won't know that only
installing `fcitx5` or `fcitx5-chinese-addons` will not make fcitx5
work. Instead,

* They should install corresponding IM module `fcitx5-frontend-gtk2`
`fcitx5-frontend-gtk3` `fcitx5-frontend-qt5` before they can virtually
input anything.
* The fcitx5 configure tool will complain about the
missing`fcitx5-config-qt` but the package name is actually
`kde-config-fcitx5`.
* They should install `fcitx5-module-dbus` to make config work.

Besides a disclaimer in /usr/share/doc/fcitx5/README.Debian , there
are no other instructions to deal with the above (of many possible)
packaging-related problems.