Added typescript to etherpad

* Fixed determining file extension.

* Added ts-node

* Fixed backend tests.

* Fixed frontend test runs.

* Fixed tests.

* Use script approach for starting etherpad.

* Change directory to src.

* Fixed env.

* Change directory

* Fixed build arg.

* Fixed docker build.

* Fixed.

* Fixed cypress file path.

* Fixed.

* Use latest node container.

* Fixed windows workflow.

* Use tsx and optimized docker image.

* Added workflow for type checks.

* Fixed.

* Added tsconfig.

* Converted more files to typescript.

* Removed commented keys.

* Typed caching middleware.

* Added script for checking the types.

* Moved SecretRotator to typescript.

* Fixed npm installation and moved to types folder.

* Use better scripts for watching typescript changes.

* Update windows.yml

* Fixed order of npm installation.

* Converted i18n.

* Added more types.

* Added more types.

* Fixed import.

* Fixed tests.

* Fixed tests.

* Fixed type checking test.

* Fixed stats

* Added express types.

* fixed.

src/tsconfig.json

@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig to read more about this file */
+    "moduleDetection": "force",
+    "lib": ["es6"],
+    /* Language and Environment */
+    "target": "es6",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    /* Modules */
+    "module": "commonjs",                                /* Specify what module code is generated. */
+    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
+    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
+    /* Type Checking */
+    "strict": true,                                      /* Enable all strict type-checking options. */
+    /* Completeness */
+    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
+  }
+}