fix(tools.app): Add tool to create html app

docs/api/source/index.rst

@@ -28,5 +28,6 @@ Welcome to Trame's documentation!
    :caption: Tools
 
    tools.www
+   tools.app
 
 .. include:: ../../../README.rst

docs/api/source/tools.app.rst

@@ -0,0 +1,18 @@
+Application file generator
+==============================
+
+This small utility let you run a command line to generate a derived HTML file
+from the original `static web client output <https://trame.readthedocs.io/en/latest/tools.www.html>`_ 
+to run a specific application from a launcher configuration.
+
+In order to use that tool, you will need to provide the path of the base
+application to use as template along with the name of the application you
+aim to run from your launcher config.
+This tool will then create a new HTML file within the same directory that
+will start the provided application name rather than the default "trame" one.
+
+
+.. code-block:: bash
+
+    python -m trame.tools.app --input ./www-content --name MySuperApp
+    # => create file MySuperApp.html from ./www-content/index.html

trame/tools/app.py

@@ -0,0 +1,58 @@
+r"""
+From the directory containing the static content for a trame application to work,
+generate another application specific HTML file.
+"""
+import argparse
+import re
+from pathlib import Path
+import sys
+
+APP_PATTERN = re.compile(r'data-app-name="\w+"')
+
+
+def create_app_file(input_file, output_file, app_name):
+    # Read in the file
+    with open(input_file, "r") as f_in:
+        content = f_in.read()
+        patched_content = APP_PATTERN.sub(f'data-app-name="{app_name}"', content)
+        with open(output_file, "w") as f_out:
+            f_out.write(patched_content)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="HTML app file generator for trame applications"
+    )
+
+    parser.add_argument(
+        "--name",
+        default="trame",
+        help="Application name to encode inside HTML {name}.html",
+    )
+
+    parser.add_argument(
+        "--input",
+        help="Input file to use as template",
+    )
+
+    args, _ = parser.parse_known_args()
+
+    # Handle input
+    input_file = Path(args.input)
+    if not input_file.exists():
+        parser.print_help()
+        sys.exit(0)
+
+    if input_file.is_dir():
+        input_file = input_file / "index.html"
+
+    if not input_file.exists():
+        parser.print_help()
+        sys.exit(0)
+
+    output_file = input_file.with_stem(args.name)
+    create_app_file(input_file, output_file, args.name)
+
+
+if __name__ == "__main__":
+    main()