Currently, the QR code image has no size specified in the HTML. This
causes other elements of the modal to jump around when opening it for
the first time and waiting for the QR image to generate. The jumping is
especially noticeable when the GUI is accessed remotely and there is a
delay while loading the elements due to slow connection.
In addition, capitalise "QR" in the alt text. This is necessary for
accessibility reasons, e.g. when using a screen reader, which may read
upper- and lowercase characters differently.
Lastly, allow to translate the alt text itself.
Signed-off-by: Tomasz Wilczyński <twilczynski@naver.com>
dab68cf841