Emit the dataChanged signal when adding or removing tags from a game.
This both updates the contents of the game's Tags column immediately
(instead of having to wait for the context menu to be closed), and
updates the sorting if games are being sorted by the Tags column.

Shows minutes/hours in the list view and handles column visibility.

Append disc label to the first disc of two-disc games too, rather than
only labelling the second disc.

A harmless case of it, but this can still cause warnings.

Fixes dynamically changing dpi scaling.
Load resources from svg if possible.
Currently svg support is not in Qt build in Externals,
and image files need to be added later.

SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.