feat: Improve way to determine and set the path containing the bash config

Before this:
The bash config repo needed to be cloned in ~/.bash/ to work properly

After this:
The bash config repo can be move anywhere (for exemple in
~/.config/bash).
The create-links.bash helper is adapted to this new behaviour.
So you can clone anywhere and call create-links.bash from anywhere. Then
the symbolic links in your home should be good and the config would load
correctly.

create-links.bash

@@ -1,11 +1,43 @@
 #!/bin/bash
 
-cd $HOME || exit 1
+# Define the path to the directory of this file if not already set
+if [ -z "${BASH_CONFIG_DIR}" ]; then
+  # Define a function to get the real path of a script
+  # (works for most cases : either sourced script or executed script, posix shells)
+  get_script_dir() {
+    local target
+    # Si appelé depuis un script (Bash), on regarde qui a appelé la fonction (${BASH_SOURCE[1]})
+    # Si la fonction est exécutée directement dans le terminal, on se rabat sur ${BASH_SOURCE[0]} ou ${0}
+    if [ -n "${BASH_SOURCE}" ]; then
+      if [ "${#BASH_SOURCE[@]}" -gt 1 ]; then
+        target="${BASH_SOURCE[1]}"
+      else
+        target="${BASH_SOURCE[0]}"
+      fi
+    elif [ -n "${ZSH_VERSION}" ]; then
+      target="${(%):-%x}"
+    else
+      target="${0}"
+    fi
 
-CONFDIR=.bash
+    # Résolution des liens symboliques POSIX
+    while [ -L "${target}" ]; do
+      local link
+      link=$(readlink "${target}")
+      case "${link}" in
+        /*) target="${link}" ;;
+        *)  target="$(dirname "${target}")/${link}" ;;
+      esac
+    done
 
-ln -sf $CONFDIR/bash_profile .bash_profile
-ln -sf $CONFDIR/bashrc .bashrc
-ln -sf $CONFDIR/bash_logout .bash_logout
+    (cd "$(dirname "${target}")" && pwd -P)
+  }
+  BASH_CONFIG_DIR=$(get_script_dir)
+fi
 
-ln -sf $CONFDIR/inputrc .inputrc
+cd "${HOME}" || exit 1
+
+ln -sf "${BASH_CONFIG_DIR}"/bash_profile .bash_profile
+ln -sf "${BASH_CONFIG_DIR}"/bashrc .bashrc
+ln -sf "${BASH_CONFIG_DIR}"/bash_logout .bash_logout
+ln -sf "${BASH_CONFIG_DIR}"/inputrc .inputrc