defaults: Add smartcard configuration

Based on https://source.puri.sm/firmware/ttxs-firmware/-/blob/purism/PURISM.md

debian/librem5-base-defaults.install

@@ -52,3 +52,7 @@ default/systemd/stop-timeout.conf	etc/systemd/user.conf.d/
 
 # initramfs modules
 default/initramfs-tools/modules.d/*	usr/share/initramfs-tools/modules.d/
+
+# smartcard configuration
+default/smartcard/librem5               etc/reader.conf.d/
+default/smartcard/pcscd.service.d       lib/systemd/system/

default/smartcard/librem5

+DEVICENAME        /dev/ttymxc2:SEC1210
+FRIENDLYNAME      "TTXS serial"
+LIBPATH           /usr/lib/pcsc/drivers/serial/libccidtwin.so

default/smartcard/pcscd.service.d/librem5.conf

+[Service]
+ExecStartPre=/bin/bash -c "echo 1 > /sys/class/leds/smc_en/brightness && sleep 5"
+ExecStopPost=/bin/bash -c "echo 0 > /sys/class/leds/smc_en/brightness"