Add a flowchart environnement and its listof

So we can more easily access those flowcharts from pdf and website,
rather than looking in the crowded list of figures.

book/baking/baking.tex

@@ -4,14 +4,14 @@ your dough into the oven. This is typically done after your
 dough has gone through the bulk fermentation and proofing stage.
 \end{quoting}
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-baking-process.tex}
   \caption[Different steaming methods]{A schematic visualization of the baking
       process using different sources of steam in a home oven.}%
   \label{fig:baking-process}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 Some other breads like flatbreads
 could also be baked on the stove. This chapter focuses on the
@@ -192,7 +192,7 @@ way.
       fluffier crumb.}%
 \end{figure}
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-dutch-oven-process.tex}
   \caption[Baking process with a dutch oven]{A visualization of the baking
@@ -203,7 +203,7 @@ way.
       darker.}%
   \label{fig:dutch-oven-process}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 Dutch ovens are an ideal way to bake with a lot of
 steam. They are not fully sealed. Regardless though,