Security fixes, enterprise stuff and more (#3241)

# Description of Changes

Please provide a summary of the changes, including:

- Enable user to add custom JAVA ops with env JAVA_CUSTOM_OPTS
- Added support for prometheus (enabled via JAVA_CUSTOM_OPTS +
enterprise license)
- Changed settings from enterprise naming to 'Premium'
- KeygenLicense Check to support offline licenses
- Disable URL-to-PDF due to huge security bug
- Remove loud Split PDF logs
- addUsers renamed to adminSettings
- Added Usage analytics page
- Add user button to only be enabled based on total users free
- Improve Merge memory usage


Closes #(issue_number)

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: a <a>
Co-authored-by: pixeebot[bot] <104101892+pixeebot[bot]@users.noreply.github.com>
Co-authored-by: Connor Yoh <[email protected]>

src/main/java/stirling/software/SPDF/controller/web/AccountWebController.java

@@ -118,11 +118,11 @@ public class AccountWebController {
 
         if (securityProps.isSaml2Active()
                 && applicationProperties.getSystem().getEnableAlphaFunctionality()
-                && applicationProperties.getEnterpriseEdition().isEnabled()) {
+                && applicationProperties.getPremium().isEnabled()) {
             String samlIdp = saml2.getProvider();
             String saml2AuthenticationPath = "/saml2/authenticate/" + saml2.getRegistrationId();
 
-            if (applicationProperties.getEnterpriseEdition().isSsoAutoLogin()) {
+            if (applicationProperties.getPremium().getProFeatures().isSsoAutoLogin()) {
                 return "redirect:" + request.getRequestURL() + saml2AuthenticationPath;
             } else {
                 providerList.put(saml2AuthenticationPath, samlIdp + " (SAML 2)");
@@ -195,7 +195,13 @@ public class AccountWebController {
     }
 
     @PreAuthorize("hasRole('ROLE_ADMIN')")
-    @GetMapping("/addUsers")
+    @GetMapping("/usage")
+    public String showUsage() {
+        return "usage";
+    }
+
+    @PreAuthorize("hasRole('ROLE_ADMIN')")
+    @GetMapping("/adminSettings")
     public String showAddUserForm(
             HttpServletRequest request, Model model, Authentication authentication) {
         List<User> allUsers = userRepository.findAll();
@@ -318,7 +324,9 @@ public class AccountWebController {
         model.addAttribute("totalUsers", allUsers.size());
         model.addAttribute("activeUsers", activeUsers);
         model.addAttribute("disabledUsers", disabledUsers);
-        return "addUsers";
+
+        model.addAttribute("maxEnterpriseUsers", applicationProperties.getPremium().getMaxUsers());
+        return "adminSettings";
     }
 
     @PreAuthorize("!hasAuthority('ROLE_DEMO_USER')")