Refactor Install script

[xtetsuji]

The installation method is redundant.

Review file copying using rcrc and creating symbolic links using Makefile, and simplify if possible.

If there is a better way to use rcrc / rcm, adopt it. It would be good if rcrc could also install using symbolic links.

It would be fine if the dotfiles to be installed could be selected in advance.

If there is a better management tool, consider introducing it.