#2270: External DB Support (#2457)

# Description

External DB support for Stirling PDF. You can now choose between the
default H2 or PostgreSQL by setting the new `enableCustomDatabase`
property to `true` or `false`.

To enable your own custom (PostgreSQL) database:
- Set `enableCustomDatabase` to `true`
- Add your database url to `customDatabaseUrl`
- Set your `username` and `password`

Closes #2270 

## Checklist

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have performed a self-review of my own code
- [x] I have attached images of the change if it is UI based
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] If my code has heavily changed functionality I have updated
relevant docs on [Stirling-PDFs doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
- [x] My changes generate no new warnings
- [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)

src/main/java/stirling/software/SPDF/model/ApplicationProperties.java

@@ -112,23 +112,6 @@ public class ApplicationProperties {
             return saml2.getEnabled() || oauth2.getEnabled();
         }
 
-        public boolean isUserPass() {
-            return (loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString())
-                    || loginMethod.equalsIgnoreCase(LoginMethods.ALL.toString()));
-        }
-
-        public boolean isOauth2Activ() {
-            return (oauth2 != null
-                    && oauth2.getEnabled()
-                    && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
-        }
-
-        public boolean isSaml2Activ() {
-            return (saml2 != null
-                    && saml2.getEnabled()
-                    && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
-        }
-
         public enum LoginMethods {
             ALL("all"),
             NORMAL("normal"),
@@ -147,6 +130,23 @@ public class ApplicationProperties {
             }
         }
 
+        public boolean isUserPass() {
+            return (loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString())
+                    || loginMethod.equalsIgnoreCase(LoginMethods.ALL.toString()));
+        }
+
+        public boolean isOauth2Activ() {
+            return (oauth2 != null
+                    && oauth2.getEnabled()
+                    && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
+        }
+
+        public boolean isSaml2Activ() {
+            return (saml2 != null
+                    && saml2.getEnabled()
+                    && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
+        }
+
         @Data
         public static class InitialLogin {
             private String username;
@@ -282,6 +282,42 @@ public class ApplicationProperties {
         private String tessdataDir;
         private Boolean enableAlphaFunctionality;
         private String enableAnalytics;
+        private Datasource datasource;
+    }
+
+    @Data
+    public static class Datasource {
+        private boolean enableCustomDatabase;
+        private String customDatabaseUrl;
+        private String type;
+        private String hostName;
+        private Integer port;
+        private String name;
+        private String username;
+        @ToString.Exclude private String password;
+    }
+
+    public enum Driver {
+        H2("h2"),
+        POSTGRESQL("postgresql"),
+        ORACLE("oracle"),
+        MYSQL("mysql");
+
+        private final String driverName;
+
+        Driver(String driverName) {
+            this.driverName = driverName;
+        }
+
+        @Override
+        public String toString() {
+            return """
+                    Driver {
+                      driverName='%s'
+                    }
+                    """
+                    .formatted(driverName);
+        }
     }
 
     @Data