feat: add methods to backup and restore Python environment

fish/functions/pythonBackup.fish

@@ -0,0 +1,3 @@
+function pythonBackup --description "Python backup"
+  pip freeze > ~/.dotfiles/python/pip-requirements.txt
+end

fish/functions/pythonRestore.fish

@@ -0,0 +1,3 @@
+function pythonRestore --description "Install Python packages"
+  pip install -r ~/.dotfiles/python/pip-requirements.txt
+end

zsh/zshrc

@@ -141,6 +141,14 @@ function homebrewRestore () {
   brew bundle --file ~/.dotfiles/Brewfile
 }
 
+function pythonBackup () {
+  pip freeze > ~/.dotfiles/python/pip-requirements.txt
+}
+
+function pythonRestore () {
+  pip install -r ~/.dotfiles/python/pip-requirements.txt
+}
+
 # Encode images in Base64
 encodeBase64() {
   uuencode -m $1 /dev/stdout | sed '1d' | sed '$d'