Beamer sidebar with sections (highlighting current)

I am currently writing a simple beamer template and have defined the footline and frametitle templates accordingly.

What I would like to add is a very simple sidebar (aligned to the right), showing the presentation title (bold) and a list of sections (current one black font, others gray).

Is there a simple way to achieve this without relying on themes like e.g. Marburg? My frametitle and footline templates span the whole paperwidth, using background images (with tikz) each. Marburg would overlap with my frametitle and footline, which is why I am not to keen on using it.

Minimal example:

\documentclass{beamer}
\usepackage{graphicx}
\usepackage{tikz}
%\usepackage{roboto}

\setlength{\unitlength}{1cm}
\beamertemplatenavigationsymbolsempty
\setbeamersize{sidebar width right=0.1\paperwidth}


\definecolor{sectioncol}{rgb}{0.99608,0.89412,0.75197}
\usebackgroundtemplate{
    \tikz[overlay, inner sep=0]
    \node[anchor=north west] {
        %\includegraphics[width=\paperwidth]{figures/header}
    };
}

\setbeamertemplate{frametitle}
{
    \leavevmode%
    \vskip 10pt
    \hskip 20pt
    \mbox{
        \textcolor{sectioncol}{\Large{\insertframetitle}}
    }
    \vskip 5pt
    \hskip 20pt
    \mbox{
        \textcolor{white}{\insertframesubtitle}
    }
}

\setbeamertemplate{footline}
{
    \leavevmode%
    \hbox{
        \parbox{20pt}{
            \hfill
        }
    }
    \hbox{
        \parbox{0.4\paperwidth}{
            test \\~\\
            \copyright test
        }
    }
    \hbox{
        \parbox{0.2\paperwidth}{
            slide <\insertpagenumber> 
        }
    }
    \hbox{
        \parbox{0.3\paperwidth}{
            \hfill
            %\includegraphics[height=0.1\paperheight]{figures/logo}
        }
    }
}

\begin{document}
\section{Graph Concepts}
\subsection{Test}
\begin{frame}
test
\end{frame}
\end{document}