Add SID for IIS_IUSRS group (jrsoftware#449)

* Add SID for IIS_IUSRS group

* Rename to `iisiusrs`.

* Document `iisiusrs` and `powerusers` in help.

* Remove `powerusers` from user and group identifiers.

ISHelp/isetup.xml

@@ -5684,6 +5684,7 @@ SignTool=byparam format c:
 <tr><td><tt>creatorowner</tt></td><td>Creator Owner</td></tr>
 <tr><td><tt>everyone</tt></td><td>Everyone group</td></tr>
 <tr><td><tt>guests</tt></td><td>Guests group</td></tr>
+<tr><td><tt>iisiusrs</tt></td><td>IIS users group</td></tr>
 <tr><td><tt>networkservice</tt></td><td>Network service account</td></tr>
 <tr><td><tt>service</tt></td><td>Local service account</td></tr>
 <tr><td><tt>system</tt></td><td>Local system account</td></tr>

Projects/Compile.pas

@@ -3127,7 +3127,8 @@     TKnownSid = record
     DOMAIN_ALIAS_RID_USERS = $00000221;
     DOMAIN_ALIAS_RID_GUESTS = $00000222;
     DOMAIN_ALIAS_RID_POWER_USERS = $00000223;
-    KnownSids: array[0..9] of TKnownSid = (
+    DOMAIN_ALIAS_RID_IIS_IUSRS = $00000238;
+    KnownSids: array[0..10] of TKnownSid = (
       (Name: 'admins';
        Sid: (Authority: (Value: (0, 0, 0, 0, 0, SECURITY_NT_AUTHORITY));
              SubAuthCount: 2;
@@ -3148,6 +3149,10 @@     TKnownSid = record
        Sid: (Authority: (Value: (0, 0, 0, 0, 0, SECURITY_NT_AUTHORITY));
              SubAuthCount: 2;
              SubAuth: (SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_GUESTS))),
+      (Name: 'iisiusrs';
+       Sid: (Authority: (Value: (0, 0, 0, 0, 0, SECURITY_NT_AUTHORITY));
+             SubAuthCount: 2;
+             SubAuth: (SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_IIS_IUSRS))),
       (Name: 'networkservice';
        Sid: (Authority: (Value: (0, 0, 0, 0, 0, SECURITY_NT_AUTHORITY));
              SubAuthCount: 1;