[PS] Start rewrite of max likelihood section

Also adds various small quality of life improvements and simpler
explanations

semester4/ps/ps-jh/parts/00_basics/05_independence.tex

@@ -1,4 +1,7 @@
 \subsection{Unabhängigkeit}
+\label{sec:basics-indep}
+\bi{Siehe zudem} Abschnitt \ref{sec:rv-indep}
+
 \shortdefinition $A, B \in \cF$ \bi{unabh.} falls $\P[A \cap B] = \P[A] \cdot \P[B]$
 
 \shortremark Falls $\P[A] \in \{0, 1\}$: $\forall B \in \cF \; \P[A \cap B] = \P[A] \P[B]$.