Hacktoberfest: Add group_odd_even_nodes algorithm to Linked Lists

[shermanhui]

Describe your change:

Adding the algorithm I used to solve
https://leetcode.com/problems/odd-even-linked-list/
for #2510

This groups odd indexed nodes in a Linked List at the beginning of the
list and then the even indexed nodes following the odd indexed nodes.

Note that the nodes are not grouped by their value but by their
index. This algo runs in O(1) space and O(n) time.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[shermanhui]

@mateuszz0000 @poyea I know the reviewers are super swamped due to the influx of Hacktoberfest PRs 😅 , but just pinging for a review here as I feel that I've taken the efforts to follow through the contributing guidelines to genuinely participate in the spirit of Hacktoberfest, but my PR was buried under a lot of invalid ones. Appreciate it! 👍

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Please reopen this pull request once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to seek help from our Gitter or ping one of the reviewers. Thank you for your contributions!