Set up Python develop environments

- use `pyenv` to manage the various develop environments
  + install several Python binaries
  + each environment receives its own `poetry` install
- add two virtual environments:
  + "interactive" => default environment with no library,
                     which receives accidental `pip install`s
  + "utils" => hosts various globally available tools/apps
               (e.g., `mackup`)
- add installation and update scripts

.config/shell/aliases.sh

@@ -80,6 +80,23 @@ alias more='less'
 alias tree='tree -C --dirsfirst'
 
 
+# Make working with Python more convenient
+
+alias py='python'
+alias ipy='ipython'
+
+if command_exists poetry; then
+    alias pr='poetry run'
+fi
+
+if command_exists pyenv; then
+    alias pyvenvs='pyenv virtualenvs --bare --skip-aliases'
+    alias pyver='pyenv version'
+    alias pyvers='pyenv versions --skip-aliases'
+    alias pywhich='pyenv which'
+fi
+
+
 # Aliases for various utilities
 alias datetime='date +"%Y-%m-%d %H:%M:%S %z (%Z)"'
 alias datetime-iso='date --iso-8601=seconds'