SSO Refactoring (#2818)

# Description of Changes

* Refactoring of SSO code around OAuth & SAML 2
* Enabling auto-login with SAML 2 via the new `SSOAutoLogin` property
* Correcting typos & general cleanup

---

## Checklist

### General

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

### Documentation

- [x] 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)
- [x] 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)

- [x] 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.

src/main/resources/templates/fragments/navbar.html

@@ -253,11 +253,11 @@
             <label for="cacheInputs" th:text="#{settings.cacheInputs.name}"></label>
           </div>
 
-          <a th:if="${@loginEnabled and @activSecurity}" th:href="@{'/account'}" class="btn btn-sm btn-outline-primary"
+          <a th:if="${@loginEnabled and @activeSecurity}" th:href="@{'/account'}" class="btn btn-sm btn-outline-primary"
             role="button" th:text="#{settings.accountSettings}" target="_blank">Account Settings</a>
         </div>
         <div class="modal-footer">
-          <a th:if="${@loginEnabled and @activSecurity}" class="btn btn-danger" role="button"
+          <a th:if="${@loginEnabled and @activeSecurity}" class="btn btn-danger" role="button"
             th:text="#{settings.signOut}" th:href="@{'/logout'}">Sign Out</a>
           <button type="button" class="btn btn-secondary" data-bs-dismiss="modal" th:text="#{close}"></button>
         </div>