Update legal URLs and improve OpenAPI metadata configuration (#3522)

# Description of Changes

Please provide a summary of the changes, including:

- Updated default Terms & Conditions URL from `/terms-and-conditions` to
`/terms` in:
  - `InitialSetup.java`
  - `settings.yml.template`
  - `allEndpointsRemovedSettings.yml`
- Improved OpenAPI metadata in `OpenApiConfig.java`:
  - Added contact information (`name`, `url`, `email`)
  - Added license section with MIT license
  - Included terms of service link
- Changed string comparison in `MetricsConfig.java` to use
`"constant".equals(...)` format
- Cleaned up and unified YAML formatting and comments
- Merged and restructured `enterpriseEdition` settings under
`premium.proFeatures`

### Why the change was made

- Ensure legal links are consistent and up-to-date
- Improve clarity and completeness of the OpenAPI specification for
external consumers
- Follow best practices for code readability and configuration structure
- Prevent misconfiguration from outdated or redundant YAML sections

---

## 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)
- [ ] 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

- [ ] 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.

src/main/resources/settings.yml.template

@@ -77,7 +77,7 @@ premium:
       appId: ''
 
 mail:
-  enabled: true # set to 'true' to enable sending emails
+  enabled: false # set to 'true' to enable sending emails
   host: smtp.example.com # SMTP server hostname
   port: 587 # SMTP server port
   username: '' # SMTP server username
@@ -85,7 +85,7 @@ mail:
   from: '' # sender email address
 
 legal:
-  termsAndConditions: https://www.stirlingpdf.com/terms-and-conditions # URL to the terms and conditions of your application (e.g. https://example.com/terms). Empty string to disable or filename to load from local file in static folder
+  termsAndConditions: https://www.stirlingpdf.com/terms # URL to the terms and conditions of your application (e.g. https://example.com/terms). Empty string to disable or filename to load from local file in static folder
   privacyPolicy: https://www.stirlingpdf.com/privacy-policy # URL to the privacy policy of your application (e.g. https://example.com/privacy). Empty string to disable or filename to load from local file in static folder
   accessibilityStatement: '' # URL to the accessibility statement of your application (e.g. https://example.com/accessibility). Empty string to disable or filename to load from local file in static folder
   cookiePolicy: '' # URL to the cookie policy of your application (e.g. https://example.com/cookie). Empty string to disable or filename to load from local file in static folder
@@ -113,11 +113,11 @@ system:
     name: postgres # set the name of your database. Should match the name of the database you create
   customPaths:
     pipeline:
-      watchedFoldersDir: '' #Defaults to /pipeline/watchedFolders
-      finishedFoldersDir: '' #Defaults to /pipeline/finishedFolders
+      watchedFoldersDir: '' # Defaults to /pipeline/watchedFolders
+      finishedFoldersDir: '' # Defaults to /pipeline/finishedFolders
     operations:
-      weasyprint: '' #Defaults to /opt/venv/bin/weasyprint
-      unoconvert: '' #Defaults to /opt/venv/bin/unoconvert
+      weasyprint: '' # Defaults to /opt/venv/bin/weasyprint
+      unoconvert: '' # Defaults to /opt/venv/bin/unoconvert
   fileUploadLimit: '' # Defaults to "". No limit when string is empty. Set a number, between 0 and 999, followed by one of the following strings to set a limit. "KB", "MB", "GB".
 
 ui: