fix: improve page numbering styles and calculation

- For improved compatibility with
  [Pympress](https://github.com/Cimbali/pympress), use the recommended
  format for PDF page numbers on notes pages. This allows presentations
  built with `show notes` on (i.e., notes on every other page) to work
  out of the box. Other notes page formats and other PDF viewers are not
  impacted.
- Change page numbering defaults to `appendixpagenumber` so that
  appendix pages are restarted from the beginning. Additionally,
  progressbar calculation will only take into account the
  `mainframenumber`, which doesn't include appendix pages.
- Remove deprecated options relating to frame numbering, as I'm not sure
  whether it impacts the change in defaults above.

src/beamerinnerthememoloch.dtx

@@ -404,7 +404,7 @@
 %    \begin{macrocode}
 \setbeamertemplate{progress bar in section page}{
   \pgfmathsetlength{\moloch@progressonsectionpage}{
-    \textwidth * min(1,\insertframenumber/\inserttotalframenumber)
+    \textwidth * min(1,\insertframenumber/\insertmainframenumber)
   }%
   \tikzexternaldisable%
   \begin{tikzpicture}[baseline=(current bounding box.north)]

src/beamerouterthememoloch.dtx

@@ -125,42 +125,23 @@
 %    \end{macrocode}%
 % \end{macro}
 %
-% \subsubsection{Deprecated Options}
-%
-% These options are deprecated and will be removed in a future version.
-%
-% \begin{macro}{numbering}
-%    Adds slide numbers to the bottom right of each slide.
-%    \begin{macrocode}
-\pgfkeys{
-  /moloch/outer/numbering/.cd,
-  .is choice,
-  none/.code={%
-      \PackageWarning{moloch}{The ``numbering'' option is deprecated.
-        Use beamer's ``page number in head/foot'' template instead}%
-      \setbeamertemplate{page number in head/foot}[default]
-    },
-  counter/.code={%
-      \PackageWarning{moloch}{The ``numbering'' option is deprecated.
-        Use beamer's ``page number in head/foot'' template instead}%
-      \setbeamertemplate{page number in head/foot}[framenumber]
-    },
-  fraction/.code={%
-      \PackageWarning{moloch}{The ``numbering'' option is deprecated.
-        Use beamer's ``page number in head/foot'' template instead}%
-      \setbeamertemplate{page number in head/foot}[totalframenumber]
-    },
-}
-%    \end{macrocode}
-% \end{macro}
-%
 % \subsubsection{Slide Numbering}
 %
 % Moloch defaults to numbering frames. To modify this, simply copy this line to your
-% preamble and replace |framenumber|.
+% preamble and replace |appendixframenumber|.
 %
 %    \begin{macrocode}
-\setbeamertemplate{page number in head/foot}[framenumber]
+\setbeamertemplate{page number in head/foot}[appendixframenumber]
+%    \end{macrocode}
+%
+% \subsubsection{Notes Page Numbering}
+%
+% Moloch defaults to numbering notes pages in a format compatible with Pympress.
+% This means that presentations using |show notes| (i.e., notes on every other
+% slide) work by default.
+%
+%    \begin{macrocode}
+\addtobeamertemplate{note page}{}{\thispdfpagelabel{notes:\insertframenumber}}
 %    \end{macrocode}
 %
 % \subsubsection{Head and footline}