Common/FileUtil: Add some missing configs to D_CONFIG_IDX

[Techjar]

This is needed otherwise the config won't be saved (except GCKEYBOARD which seems to be handled elsewhere, but it doesn't hurt to add it here anyways). Only affected Linux, somehow Windows saves just fine. Must be a different code path somewhere.

[JMC47]

@iwubcode please review.

[iwubcode]

Thanks @Techjar ! This looks ok to me. I'm guessing windows is using the "USER" path: https://github.com/dolphin-emu/dolphin/pull/9780/files#diff-25b1e5a1a176c6bfa1e888cde0940d6df39945077b6bd47b5890787f2456e19eL924 . But that's just a guess. I can't recall how that's working.

Note you can't actually override freelook settings in user config without an additional change. I made that in #9779 but it probably should be pulled out (see this commit) since that review is quite large.

[JosJuice]

Could you add F_DUALSHOCKUDPCLIENTCONFIG_IDX too? LGTM otherwise.