Make xhtml2pdf and python-bidi optional dependencies for PDF support

python-bidi >= 0.5.0 requires Rust/maturin to build from source, which
fails on platforms like Termux (Android) that lack a Rust toolchain.

Since PDF report generation is an optional feature (--pdf flag), move
xhtml2pdf (which depends on python-bidi, arabic-reshaper, reportlab)
to an optional extras group. Users can install PDF support with:
  pip install maigret[pdf]

Also add graceful error handling in save_pdf_report() when xhtml2pdf
is not installed, with a clear message about how to install it.

Agent-Logs-Url: https://github.com/soxoj/maigret/sessions/ab19aa96-7175-47bd-af88-34b3106269e9

Co-authored-by: soxoj <31013580+soxoj@users.noreply.github.com>

opensuse.txt

@@ -8,7 +8,6 @@
 aiodns>=3.0.0
 aiohttp>=3.8.6
 aiohttp-socks>=0.7.1
-arabic-reshaper~=3.0.0
 async-timeout
 attrs>=22.2.0
 certifi>=2023.7.22
@@ -24,9 +23,7 @@ MarkupSafe
 mock>=4.0.3
 multidict
 pycountry>=22.3.5
-PyPDF2>=3.0.1
 PySocks>=1.7.1
-python-bidi>=0.4.2
 requests
 requests-futures>=1.0.0
 six>=1.16.0
@@ -37,11 +34,12 @@ torrequest>=0.1.0
 tqdm
 typing-extensions
 webencodings>=0.5.1
-svglib
-xhtml2pdf~=0.2.11
 XMind>=1.2.0
 yarl
 networkx
 pyvis>=0.2.1
-reportlab
 cloudscraper>=1.2.71
+# Optional PDF dependencies (install separately for PDF report support):
+# xhtml2pdf~=0.2.11
+# arabic-reshaper~=3.0.0
+# reportlab