move global styling here, remove unneeded package

preamble.tex

@@ -10,13 +10,11 @@
     % Refer to https://ftp.tu-chemnitz.de/pub/tex/fonts/frcursive/frcursive.pdf for how to use it
 \renewcommand{\familydefault}{\sfdefault} % Sets default font, to default serif-font (i.e. "Sans-serif")
 % Page margins
-\usepackage[top=2cm,left=2cm,right=1cm,bottom=2cm]{geometry} % "showframe" parameter was here, don't know why
+\usepackage[top=2cm,left=2cm,right=1cm,bottom=2cm]{geometry}
 % Colors
 \usepackage{xcolor}
 % Graphics
 \usepackage{graphicx}
-% Provides \Ifthispageodd to decide where to place stuff that spreads multiple pages
-\usepackage{scrextend}
 % Customize titles
 \usepackage[explicit]{titlesec}
 % Customize headers and footers
@@ -51,10 +49,8 @@
 % Handles paragraph and TOC spacing and indentation
 \usepackage[indent=0pt,tocskip=0pt]{parskip}
 
-% !!!
-% This modifies the settings for line breaks and suppresses most
-% "overfull"/"underfull"  errors. THESE SETTINGS ARE FAR FROM IDEAL!
-% !!!
+%%% This modifies the settings for line breaks and suppresses most
+% "overfull"/"underfull"  errors! THESE SETTINGS ARE FAR FROM IDEAL! !!!
 \emergencystretch = 0pt
 \pretolerance = 150
 \tolerance = 10001
@@ -62,9 +58,19 @@
 \vbadness 10000
 \hfuzz = 320pt
 
-% No idea what these do
-\fancyhf{}
-\cfoot{\thepage}
+% Pagestyle
+\fancypagestyle{plain}{
+    \renewcommand{\headrulewidth}{0pt}
+    \fancyhf{}
+    \fancyfoot[LE,RO]{\thepage}
+}
 
-% Set some other counter? This is actually somehow important, but again, wasn't me.
-\setcounter{secnumdepth}{0}
\ No newline at end of file
+% Set some other counter? This is actually somehow important, but wasn't me.
+\setcounter{secnumdepth}{0}
+
+% Time format
+\DTMnewtimestyle{hhmm}{%
+    % \DTMdisplaytime{<hh>}{<mm>}{<ss>}
+    \renewcommand{\DTMdisplaytime}[3]{\DTMtwodigits{##1}:\DTMtwodigits{##2} Uhr}
+}
+\DTMsettimestyle{hhmm} % sets style