[Pale-Moon] Issue #1782 - Add option to insert all new tabs after the current tab

This adds 'browser.tabs.insertAllAfterCurrent' as a preference which
makes all new tabs opened to be next to the currently active tab, instead
of at the end - regardless if the tab is considered "related" to the active
tab. This (naturally and logically) overrides 'insertRelatedAfterCurrent'

Resolves #1782

application/palemoon/app/profile/palemoon.js

@@ -433,6 +433,7 @@ pref("browser.link.open_newwindow.disabled_in_fullscreen", false);
 // Tabbed browser
 pref("browser.tabs.autoHide", false);
 pref("browser.tabs.closeWindowWithLastTab", true);
+pref("browser.tabs.insertAllAfterCurrent", false);
 pref("browser.tabs.insertRelatedAfterCurrent", true);
 pref("browser.tabs.warnOnClose", true);
 pref("browser.tabs.warnOnCloseOtherTabs", true);

application/palemoon/base/content/tabbrowser.xml

@@ -1734,13 +1734,15 @@
               this._outerWindowIDBrowserMap.set(b.outerWindowID, b);
             }
 
-            // Check if we're opening a tab related to the current tab and
-            // move it to after the current tab.
-            // aReferrerURI is null or undefined if the tab is opened from
+            // Check if the user prefers inserting all new tabs after the current tab.
+            // If not, check if we're opening a tab related to the current tab.
+            // If either condition is met, move the new tab to after the current tab.
+            // Note: aReferrerURI is null or undefined if the tab is opened from
             // an external application or bookmark, i.e. somewhere other
             // than the current tab.
-            if ((aRelatedToCurrent == null ? aReferrerURI : aRelatedToCurrent) &&
-                Services.prefs.getBoolPref("browser.tabs.insertRelatedAfterCurrent")) {
+            if (Services.prefs.getBoolPref("browser.tabs.insertAllAfterCurrent", false) || 
+                ((aRelatedToCurrent == null ? aReferrerURI : aRelatedToCurrent) &&
+                 Services.prefs.getBoolPref("browser.tabs.insertRelatedAfterCurrent"))) {
               let newTabPos = (this._lastRelatedTab ||
                                this.selectedTab)._tPos + 1;
               if (this._lastRelatedTab)