Chore: Improve idle memory via more lazy imports (#14599)

* Chore: Import dateparser lazily so processes that never parse dates skip it

* Chore: Import turbohtml lazily in the mail parser

* Chore: Import lxml lazily in the SVG validator

* Chore: Import paperless_ai.indexing lazily in document tasks

* Chore: Import paperless_ai helpers lazily in views

* Chore: Read the OCRmyPDF sRGB profile on first use instead of at import

* Chore: Import pikepdf and img2pdf lazily so startup does not load them

* Chore: Reuse the initialized Django ASGI application for HTTP routing

src/paperless/validators.py

@@ -3,7 +3,6 @@ from io import BytesIO
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.core.files.uploadedfile import UploadedFile
-from lxml import etree
 from PIL import Image
 
 ALLOWED_SVG_TAGS: set[str] = {
@@ -186,6 +185,7 @@ def reject_dangerous_svg(file: UploadedFile) -> None:
     Raises ValidationError if unsafe content is found.
     See GHSA-6p53-hqqw-8j62
     """
+    from lxml import etree
 
     try:
         parser = etree.XMLParser(resolve_entities=False)