refactor: rename the application package to docsgpt

The backend import package is now docsgpt, the name it will carry on PyPI;
application was far too generic to install into anyone's site-packages.
git mv plus a mechanical rewrite of every import, dotted string and path
reference: 734 Python files, the compose files, Dockerfile, workflows, docs,
setup scripts, devcontainer, k8s manifests, vscode config, pytest and coverage
config, .gitignore. Behaviour is unchanged.

Kept for one release:
- A top-level application package whose meta-path finder resolves
  application.x.y to the already-imported docsgpt.x.y object, so old imports
  and entry points (celery -A application.app.celery,
  uvicorn application.asgi:asgi_app) keep working with a FutureWarning.
- Celery registers every application.* task name as an alias of its
  docsgpt.* task on start-up, so messages queued by the previous release still
  run. The redbeat key prefix moves to redbeat:docsgpt:v2: so schedule entries
  the previous release wrote are left unread instead of firing twice.

The backend image builds from the repository root (docker build -f
docsgpt/Dockerfile .) so it can ship the alias package; a root .dockerignore
allow-lists docsgpt/ and application/ and keeps caches, local data, .env
files, the sample index files and the Dockerfile out. Compose and the image
workflows point at the new context.

docsgpt/parser/file/pptx_parser.py

@@ -0,0 +1,75 @@
+"""PPT parser.
+Contains parsers for presentation (.pptx) files to extract slide text.
+"""
+from pathlib import Path
+from typing import Any, Dict, List, Union
+
+from docsgpt.parser.file.base_parser import BaseParser
+
+class PPTXParser(BaseParser):
+    r"""PPTX (.pptx) parser for extracting text from PowerPoint slides.
+    Args:
+        concat_slides (bool): Specifies whether to concatenate all slide text into one document.
+            - If True, slide texts will be joined together as a single string.
+            - If False, each slide's text will be stored as a separate entry in a list.
+            Set to True by default.
+        slide_separator (str): Separator used to join slides' text content.
+            Only used when `concat_slides=True`. Default is "\n".
+        Refer to https://python-pptx.readthedocs.io/en/latest/ for more information.
+    """
+
+    def __init__(
+        self,
+        *args: Any,
+        concat_slides: bool = True,
+        slide_separator: str = "\n",
+        **kwargs: Any
+    ) -> None:
+        """Init params."""
+        super().__init__(*args, **kwargs)
+        self._concat_slides = concat_slides
+        self._slide_separator = slide_separator
+
+    def _init_parser(self) -> Dict:
+        """Init parser."""
+        return {}
+
+    def parse_file(self, file: Path, errors: str = "ignore") -> Union[str, List[str]]:
+        r"""
+        Parse a .pptx file and extract text from each slide.
+        Args:
+            file (Path): Path to the .pptx file.
+            errors (str): Error handling policy ('ignore' by default).
+        Returns:
+            Union[str, List[str]]: Concatenated text if concat_slides is True,
+            otherwise a list of slide texts.
+        """
+
+        try:
+            from pptx import Presentation
+        except ImportError:
+            raise ImportError("pptx module is required to read .PPTX files.")
+
+        try:
+            presentation = Presentation(file)
+            slide_texts=[]
+
+            # Iterate over each slide in the presentation
+            for slide in presentation.slides:
+                slide_text=""
+
+                # Iterate over each shape in the slide
+                for shape in slide.shapes:
+                    # Check if the shape has a 'text' attribute and append that to the slide_text
+                    if hasattr(shape,"text"):
+                        slide_text+=shape.text
+
+                slide_texts.append(slide_text.strip())
+
+            if self._concat_slides:
+                return self._slide_separator.join(slide_texts)
+            else:
+                return slide_texts
+
+        except Exception as e:
+            raise e