Refactor README

Add new option, and have install script mention README for details.

src/install/ssh-cryptsetup

@@ -54,7 +54,7 @@ build() {
 
   # Note: parts of this script (modules/binaries/files added) are the same than
   # other install scripts (/usr/lib/initcpio/install/):
-  #   - 'encryp': nominal support of encrypted volumes at boot time
+  #   - 'encrypt': nominal support of encrypted volumes at boot time
   #   - 'net': network tools
 
   ## Modules
@@ -129,27 +129,8 @@ Network is configured with 'ip=' kernel parameter (see 'mkinitcpio-nfs-utils').
 Authorized SSH key(s) must be present in '/etc/dropbear/initrd.authorized_keys'.
 LUKS encrypted devices to unlock are derived from '/etc/crypttab', which must
 be present.
-Some options can be set in '/etc/initcpio/sshcs_env' (file is sourced in
-initrd shell):
- * 'sshcs_opt_debug': whether to be more verbose about ongoing actions
-   - default: '0'
-   - any non-zero value to enable
- * 'sshcs_opt_net_wol': Wake-on-LAN option to set on network device
-   - default: 'g' (MagicPacket™)
-   - usually WOL is disabled once in initramfs shell
-   - set empty to not change network device WOL setting
- * 'sshcs_opt_timeout_ipconfig': time (in seconds) to configure IP
-   - default: '10'
- * 'sshcs_opt_listen': SSH listening port
-   - default: '22'
- * 'sshcs_opt_timeout_poweroff': time (in seconds) to unlock devices before
-   automatic powering off
-   - default (and minimum value): '120' (2 minutes)
-   - negative value to deactivate
- * 'sshcs_opt_use_shell': whether to start a full 'ash' shell
-   - default: '0'
-   - '1' to enable
-   - when disabled (the default), a script to unlock devices is executed instead
+Some options can be set in '/etc/initcpio/sshcs_env'.
+See the README for more details.
 
 Each SSH server key ('dropbear_rsa_host_key', 'dropbear_ecdsa_host_key' and
 'dropbear_ed25519_host_key' in '/etc/dropbear' folder) is imported from OpenSSH