systemd: Update for system install — heartwood

While these unit files were good for a user install, they were not appropriate for running system services. Since most users nowadays use rad node to manage their node, it makes more sense for the unit files to be oriented towards server use.

 # When running radicle-httpd on a server, it should be run as a separate user.
 #
 # Copy this file into /etc/systemd/system and set the User/Group parameters
 # under [Service] appropriately, or copy it into the user's systemd directory.
 #
 # For example:
 #
 #   mkdir -p $HOME/.config/systemd/user/
 #   cp radicle-node.service $HOME/.config/systemd/user/radicle-node.service
 # under [Service] appropriately, as well as the `RAD_HOME` environment variable.
 #
 [Unit]
 After=syslog.target network.target
 Description=Radicle HTTPd
 Description=Radicle HTTP Daemon
 After=network.target network-online.target
 Requires=network-online.target
 [Service]
 ExecStart=%h/.radicle/bin/radicle-httpd --listen 127.0.0.1:8080
 Environment=RAD_HOME=%h/.radicle RUST_BACKTRACE=1 RUST_LOG=info
 User=seed
 Group=seed
 ExecStart=/usr/local/bin/radicle-httpd --listen 127.0.0.1:8080
 Environment=RAD_HOME=/home/seed/.radicle RUST_BACKTRACE=1 RUST_LOG=info
 KillMode=process
 Restart=always
 RestartSec=1
 [Install]
 WantedBy=default.target
 WantedBy=multi-user.target

 # When running radicle-node on a server, it should be run as a separate user.
 #
 # Copy this file into /etc/systemd/system and set the User/Group parameters
 # under [Service] appropriately, or copy it into the user's systemd directory.
 #
 # For example:
 #
 #   mkdir -p $HOME/.config/systemd/user/
 #   cp radicle-node.service $HOME/.config/systemd/user/radicle-node.service
 # under [Service] appropriately, as well as the `RAD_HOME` environment variable.
 #
 # If your Radicle key is passphrase-protected, you will have to set the
 # RAD_PASSPHRASE environment variable to the passphrase supplied during
 # `RAD_PASSPHRASE` environment variable to the passphrase supplied during
 # `rad auth`, eg.
 #
 #   [Service]
 #   Environment=RAD_PASSPHRASE=snickerdoodle
 #
 # Also ensure RAD_HOME is set appropriately.
 #
 [Unit]
 Description=Radicle Node
 After=syslog.target network.target
 After=network.target network-online.target
 Requires=network-online.target
 [Service]
 ExecStart=%h/.radicle/bin/radicle-node --listen 0.0.0.0:8776 --force
 Environment=RAD_HOME=%h/.radicle RUST_BACKTRACE=1 RUST_LOG=info
 User=seed
 Group=seed
 ExecStart=/usr/local/bin/radicle-node --listen 0.0.0.0:8776 --force
 Environment=RAD_HOME=/home/seed/.radicle RUST_BACKTRACE=1 RUST_LOG=info
 KillMode=process
 Restart=always
 RestartSec=3
 [Install]
 WantedBy=default.target
 WantedBy=multi-user.target