Uninstallation is not clean, allow user-specified installation directory

The install page says: > To uninstall TinyTeX, simply delete the folder from your file manager/browser, or use command line: ``` # Linux tlmgr path remove rm -r ~/.TinyTeX ``` > Compare the way to uninstall TinyTeX with the ways to uninstall other LaTeX distributions, and you may appreciate how much simpler it is to get rid of TinyTeX than other LaTeX distributions. That is because TinyTeX is just a self-contained folder. So, what about the now-broken symlinks in `/home/user/.local/bin`? Please allow users to choose the installation directory, and whether or not to create symlinks in system folders. While providing symlinks in ~/.local/bin saves the step of adding `export PATH=` to `~/.bashrc` or similar, it means one has to retain a list of the files to remove to properly uninstall tinytex.