etherpad: switch default DB to sqlite + use canonical ether/etherpad repo refs

- ct/etherpad.sh + install/etherpad-install.sh: use ether/etherpad
  (canonical name; ether/etherpad-lite still redirects but the new
  name is preferred)
- install/etherpad-install.sh: switch dbType from dev-only "dirty"
  to sqlite at /var/lib/etherpad/etherpad.db on first config seed;
  matches the same default we land on across the snap, .deb, and
  Home Assistant add-on packagings
- json/etherpad.json: refresh note to reflect the sqlite default
  and document postgres/mysql as alternatives via dbType/dbSettings

ct/etherpad.sh

@@ -29,7 +29,7 @@ function update_script() {
     exit
   fi
 
-  if check_for_gh_release "etherpad-lite" "ether/etherpad-lite"; then
+  if check_for_gh_release "etherpad-lite" "ether/etherpad"; then
     msg_info "Stopping Service"
     systemctl stop etherpad
     msg_ok "Stopped Service"
@@ -39,7 +39,7 @@ function update_script() {
     [ -d /opt/etherpad-lite/var ] && cp -a /opt/etherpad-lite/var /opt/etherpad-var.bak
     msg_ok "Backed up Configuration"
 
-    CLEAN_INSTALL=1 fetch_and_deploy_gh_release "etherpad-lite" "ether/etherpad-lite" "tarball" "latest" "/opt/etherpad-lite"
+    CLEAN_INSTALL=1 fetch_and_deploy_gh_release "etherpad-lite" "ether/etherpad" "tarball" "latest" "/opt/etherpad-lite"
 
     msg_info "Rebuilding Etherpad"
     cd /opt/etherpad-lite