enable support for system wide dotfiles lookup

[Bhupesh-V]

dotman works with an assumption that all dotfiles are present inside the $HOME directory.

This might not always be true. For e.g, some user programs store config (or dotfiles) inside the ~/.comfig/ folder as well, An example of this is the neovim default config which is present under .config/nvim/init.vim.

To fix this, we need to search the version of files present inside the user's dotfiles repo to that of inside our system & then check diff.

There can be room for improvement in this as well.

UPDATE: this will also lift the dependency of every filename to start with a . (dotfile, Get it?), i.e dotman would be able to handle your shell scripts as well 🎉 🧡

Please comment below what & how will you be approaching this before sending any PRs