etc/{i2pd,systemd}: modernise to less bad ideas

The issue has been fixed last year and considering I2Pd can connect
through Yggdrasil natively, tunneling Yggdrasil in is a bad idea and
could lead into Yggdrasil over Yggdrasil loop situation.

etc/i2pd/tunnels.conf.d/yggdrasil-in.conf

@@ -1,7 +0,0 @@
-[yggdrasil-in]
-type = server
-host = 127.0.0.1
-port = 63412
-keys = yggdrasil-in.dat
-inbound.length = 2
-outbound.length = 2

etc/systemd/system/i2pd.service

@@ -1,38 +0,0 @@
-[Unit]
-Description=I2P Router written in C++
-Documentation=man:i2pd(1) https://i2pd.readthedocs.io/en/latest/
-After=network.target
-
-[Service]
-User=i2pd
-Group=i2pd
-RuntimeDirectory=i2pd
-RuntimeDirectoryMode=0700
-LogsDirectory=i2pd
-LogsDirectoryMode=0700
-Type=forking
-# Mikaela: my only modification, removing routerinfo and sleeping
-# to workaround https://github.com/PurpleI2P/i2pd/issues/1275
-ExecStartPre=/bin/rm -f /var/lib/i2pd/routerinfo
-ExecStartPre=/bin/sleep 15
-# Mikaela: normal commands
-ExecStart=/usr/sbin/i2pd --conf=/etc/i2pd/i2pd.conf --tunconf=/etc/i2pd/tunnels.conf --tunnelsdir=/etc/i2pd/tunnels.conf.d --pidfile=/var/run/i2pd/i2pd.pid --logfile=/var/log/i2pd/i2pd.log --daemon --service
-ExecReload=/bin/kill -HUP $MAINPID
-PIDFile=/var/run/i2pd/i2pd.pid
-### Uncomment, if auto restart needed
-#Restart=on-failure
-
-KillSignal=SIGQUIT
-# If you have the patience waiting 10 min on restarting/stopping it, uncomment this.
-# i2pd stops accepting new tunnels and waits ~10 min while old ones do not die.
-#KillSignal=SIGINT
-#TimeoutStopSec=10m
-
-# If you have problems with hanging i2pd, you can try increase this
-LimitNOFILE=4096
-# To enable write of coredump uncomment this
-#LimitCORE=infinity
-PrivateDevices=yes
-
-[Install]
-WantedBy=multi-user.target

etc/systemd/system/i2pd.service.d/mullvad-exclude.conf

@@ -0,0 +1,5 @@
+# https://i2pd.readthedocs.io/en/latest/tutorials/yggdrasil-only-mode/
+# and letting it through Mullvad this way
+ExecStartPre=/usr/bin/sleep 30
+ExecStart=
+ExecStart=/usr/bin/mullvad-exclude /usr/sbin/i2pd --conf=/etc/i2pd/i2pd.conf --tunconf=/etc/i2pd/tunnels.conf --tunnelsdir=/etc/i2pd/tunnels.conf.d --pidfile=/run/i2pd/i2pd.pid --logfile=/var/log/i2pd/i2pd.log --daemon --service

etc/systemd/system/i2pd.service.d/override.conf

@@ -1,3 +0,0 @@
-[Service]
-ExecStartPre=/bin/rm -f /var/lib/i2pd/routerinfo
-ExecStartPre=/bin/sleep 15