build: refactor configure.py

[VoltrexKeyva]

• Explicitly specify the encoding when opening files.
• Use f-strings to format strings.
• Use isinstance() for type checks instead of type().
• Use the with keyword for resource-allocating operations.
• Avoid using multiple statements in a single line.
• Remove unnecessary else clauses after return.
• Iterate with the items() method of dictionaries when both the key and value are used.
• Remove unnecessary parentheses.
• Rename unused unpacked variables to _, _1, etc etc.
• Rename the list variable to avoid conflict with the global list() function.
• Remove unused path parameter of the icu_download() function.
• Use the pathlib library for paths instead of os.path.