Corrected use of Plesk API calls to fetch all domain for all Plesk editions

This implementation of the Plesk API will add support for Plesk web admin edition and will now discover all domains ( of customers & administrative users) managed by the specific plesk instance.

The previous implementation of the Plesk API uses the customer API. This brings two problems:
1. The current API call only fetches the domains of resellers/customers and not the domains that are managed by administrative users.
compare:
https://docs.plesk.com/en-US/obsidian/api-rpc/about-xml-api/reference/managing-customer-accounts/retrieving-the-list-of-customer%E2%80%99s-domains.75309/
https://docs.plesk.com/en-US/obsidian/api-rpc/about-xml-api/reference/managing-plesk-server/getting-server-information/response-packet-structure-and-samples/list-of-domains.75294/

2. The customer API is only available in the web pro/host editions. The most common license on VPS/Dedicated Servers is nowadays the web admin edition. See: https://www.plesk.com/editions/

The correct way to get all domains in all Plesk editions is to use the Sites (Domains) API:
https://docs.plesk.com/en-US/obsidian/api-rpc/about-xml-api/reference/managing-sites-domains/getting-information-about-sites.66583/
This way is working for all plesk editions the same way.

dnsapi/dns_pleskxml.sh

@@ -41,7 +41,7 @@ pleskxml_init_checks_done=0
 NEWLINE='\
 '
 
-pleskxml_tplt_get_domains="<packet><customer><get-domain-list><filter/></get-domain-list></customer></packet>"
+pleskxml_tplt_get_domains="<packet><webspace><get><filter/><dataset><gen_info/></dataset></get></webspace></packet>"
 # Get a list of domains that PLESK can manage, so we can check root domain + host for acme.sh
 # Also used to test credentials and URI.
 # No params.
@@ -375,7 +375,7 @@ _pleskxml_get_root_domain() {
   # Output will be one line per known domain, containing 2 <name> tages and a single <id> tag
   # We don't actually need to check for type, name, *and* id, but it guarantees only usable lines are returned.
 
-  output="$(_api_response_split "$pleskxml_prettyprint_result" 'domain' '<type>domain</type>' | sed 's/<ascii-name>/<name>/g;s/<\/ascii-name>/<\/name>/g' | grep '<name>' | grep '<id>')"
+  output="$(_api_response_split "$pleskxml_prettyprint_result" 'result' '<status>ok</status>' | sed 's/<ascii-name>/<name>/g;s/<\/ascii-name>/<\/name>/g' | grep '<name>' | grep '<id>')"
 
   _debug 'Domains managed by Plesk server are (ignore the hacked output):'
   _debug "$output"