Change --text from argument to option

This is a breaking change. It puts text on the same level as the other options like image or barcode.
It is breaking because it now requires any text to be preceeded by `--text`.

Ref: <#12 (comment)> and below.

Author: maresb

src/labelle/cli/cli.py

@@ -130,7 +130,7 @@ def default(
     ] = None,
     text: Annotated[
         Optional[List[str]],
-        typer.Argument(
+        typer.Option(
             help="Text, each parameter gives a new line",
             rich_help_panel="Elements",
         ),