Since _ls is now deprecated this is removed in favour of L1, I've also taken the oportunity to replace QStringLiteral and QLatin1String with their shortened form while we're at it.
There are also a few instances where the string literal type has been switch, the general rule being to use the one that matches the function type or value being compared to avoid conversions.
Note this technically won't build for now because of the lack of RoomMember support but I'll push that at the quotient-next branch next.
This is needed as well to get a branch that builds on dev.
