Add base configuration

- Follow XDG standard: ~/.config and ~/.local folders
- Set environment variables and define aliases within ~/.config/shell
- Add installation script for easy setup
- Add README.md with info on the installation and general notes

.bashrc

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+# `bash`-specific configurations
+
+
+# Load configuration files common to all kinds of shells,
+# if not already done by a `bash` login shell
+[ -z "$PROFILE_LOADED" ] && [ -f "$HOME/.profile" ] && . "$HOME/.profile"