Improve manage versions py

[rffontenelle]

Rename updpyver.py script to manage_versions.py and change its use.

Changes involved:

• manage_versions.py update_versions_file does the same as the original purpose: fetch Python versions and write to .github/versions.txt file
• New arguments: all, current, others
• manage_versions.py all prints all versions from file as a list. E.g., ['3.12', '3.11', '3.10', '3.9', '3.8']
• manage_versions.py current prints only the latest version currently used in translation. E.g., '3.12'
• manage_versions.py others prints all versions except for the current one. E.g., ['3.11', '3.10', '3.9', '3.8'] ('3.12' excluded)