Awesome CV is LaTeX template for a CV(Curriculum Vitae), Résumé or Cover Letter inspired by Fancy CV. It is easy to customize your own template, especially since it is really written by a clean, semantic markup.

TeX Live is an "easy way to get up and running with the TeX document production system. It provides a comprehensive TeX system with binaries for most flavors of Unix, including GNU/Linux, and also Windows. It includes all the major TeX-related programs, macro packages, and fonts that are free software, including support for many languages around the world."

TeX Live is one of the most popular distributions for LaTeX, ConTeXt and friends.

The quickest way to check if a package is installed is to search for it with kpsewhich {package-name}.sty. So, to check for etoolbox, use

$ kpsewhich etoolbox.sty
/usr/local/texlive/2014/texmf-dist/tex/latex/etoolbox/etoolbox.sty

If it finds the package, it will output the path (just like normal which). If it doesn't find the package, it will output nothing and have a non-zero exit code.

Perhaps the most direct way to answer the question though would be to try and use the package:

\documentclass{article}
\usepackage{etoolbox}
\begin{document}
\end{document}

The above will fail if etoolbox cannot be found.

If you installed TeXLive via the Arch repositories, you can look up the installed packages in the files located in:

/var/lib/texmf/arch/installedpkgs/*.pkgs

On Manjaro there might be similar files or the same in a different (or same?) path (I don't know, because the Manjaro-Wiki includes no article about its TeXLive).