Convert Dart GitHub "Line Counting" action to Python3

[palisadoes]

Is your feature request related to a problem? Please describe.

Issue #700 was created to help improve Dart file code quality by limiting the size of files submitted in pull requests. This issue was closed with pull request #724

PR #724 created these two files:

1. countline.sh
2. countlines.yml

Describe the solution you'd like

1. We need the countline.sh script converted to python3. It's a more universally taught language and will make future support easier.
2. We need countlines.yml to reference the new python3 file.
3. The code must:
   1. comply with the Google Python Style Guide which is heavily based on passing the pylint checks.
   2. Pass the pydocstyle, pycodestyle and pep8 tests that can be installed using pip3. Most commonly used IDEs (atom.io) support including these packages and pylint. The IDE will alert you to non compliance
4. Delete the countline.sh script
5. The python3 script must:
   1. exit with a code 0 when successful and code 1 when it fails
   2. have identical text output to the current script.
   3. be proven to work as a GitHub action as part of the PR process

Describe alternatives you've considered

N/A

Approach to be followed (optional)

See section above

Additional context

Kudos to @StrangeNoob for working on the original issue, who may be able to provide some guidance.

[sumitra19jha]

@palisadoes I have previously worked in Python 3 but I have never implemented this work in any of the previous flutter projects I have worked on. But still, I would like to take up this issue and resolve it. It will increase my knowledge.

[palisadoes]

1. Use os.walk
2. Here's an example

Please focus on readability and compliance with the pip3 packages mentioned.

[sumitra19jha]

Sure @palisadoes

[palisadoes]

@sumitra19jha Also use Argparse instead of getting the argument using $1

[sumitra19jha]

@sumitra19jha Also use Argparse instead of getting the argument using $1

Ok I will do that