Linux checkcreds pointer verification improvements

[gcmoreira]

In the context of #1243 this PR improves the smear memory protection for the Check_creds plugin.

This PR also includes:

• Adding plugin version
• Adding a new column (cred virtual address) to give the user more context about where to find that information in memory.
• Removing unused logging module

Lastly, part of the code has been refactored to be more Pythonic, improving readability and efficiency.

[ikelos]

Looks good, thanks!