Add support for tool.poetry.include

[Nealium]

Closes #10 and added pipx inject install method to README as self add "may be problematic" 🤷

Development flow with pipx:

# install 
pipx runpip poetry install dist/{some_wheel}.whl

# uninstall
pipx runpip poetry uninstall poetry-pyinstaller-plugin

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Edit

I've kept it as two commits in case a roll back needs to happen. I didn't want to make two pull requests as "extended_includes" requires "includes"

include_extended explained

The problem with a 1-1 with Poetry's include is that:

1. You cannot include directories, It will loosely place files into _internal
2. You cannot put files next to the pyinstaller executable. A included README would be placed into _internal and with a onefile install it would be worse than useless.
3. You cannot rename files. Ex: ENDUSER_README.md -> README.md

To add this functionality I've added three new settings:

1. [poetry-pyinstaller-plugin.exclude-include] (boolean=false)
   • disables plugin's features for base poetry.include packing
2. [poetry-pyinstaller-plugin.include] (dict[source, destination])
   • a 1-1 mapping for --add-data
   • allows for destination renaming
   • allows for entire directories to be copied
3. [poetry-pyinstaller-plugin.package] (dict[source, destination])
   • adds the ability to place files or directories next to the pyinstaller executable
   • destination renaming

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[poetry-pyinstaller-plugin.package] caveat

It doesn't support creating nested destinations.

Example:

This does not work:

[tool.poetry-pyinstaller-plugin.package]
"README.md" = "docs/README.md"  # docs directory doesn't exist!

This does work:

[tool.poetry-pyinstaller-plugin.package]
"docs" = "."                    # create directory
"README.md" = "docs/README.md"  # place into directory