Delete install scripts whose job is now done by package files

Each of these scripts only wrote a single /etc file (or copied
config/bashrc into the user home). The corresponding files now ship
from the omarchy-settings package — either directly into /etc (drop-ins
the package fully owns) or via the /usr/share/omarchy/etc-overrides
post_install dance (for upstream-owned paths).

Deleted:
- install/config/timezones.sh          -> etc/sudoers.d/omarchy-tzupdate
- install/config/sudoless-asdcontrol.sh -> etc/sudoers.d/omarchy-asdcontrol
                                          ($USER rewritten to %wheel)
- install/config/increase-sudo-tries.sh -> etc/sudoers.d/omarchy-passwd-tries
                                          (faillock.conf side now in etc-overrides)
- install/config/hardware/ignore-power-button.sh
                                        -> etc/systemd/logind.conf.d/10-ignore-power-button.conf
                                          (replaces sed-edit of logind.conf)
- install/config/hardware/usb-autosuspend.sh
                                        -> etc/modprobe.d/omarchy-usb-autosuspend.conf
- install/config/ssh-flakiness.sh       -> etc/sysctl.d/99-omarchy-sysctl.conf
- install/config/config.sh              -> /etc/skel seeds ~/.config from config/**;
                                          ~/.bashrc seeded from etc-overrides
- install/login/plymouth.sh             -> theme files already shipped by
                                          omarchy-settings; etc/plymouth/plymouthd.conf
                                          handled via etc-overrides

A separate migration tidies up the old paths on existing installs.
all.sh entries updated to drop these scripts.

install/config/hardware/ignore-power-button.sh

@@ -1,2 +0,0 @@
-# Disable shutting system down on power button to bind it to power menu afterwards
-sudo sed -i 's/.*HandlePowerKey=.*/HandlePowerKey=ignore/' /etc/systemd/logind.conf

install/config/hardware/usb-autosuspend.sh

@@ -1,5 +0,0 @@
-# Disable USB autosuspend to prevent peripheral disconnection issues
-if [[ ! -f /etc/modprobe.d/disable-usb-autosuspend.conf ]]; then
-  echo "options usbcore autosuspend=-1" | sudo tee /etc/modprobe.d/disable-usb-autosuspend.conf
-fi
-