Replace blacklist_ with exclude_ in config keys and error messages

[ogarrett]

For diversity/inclusion reasons, replace 'blacklist' with 'exclude':

Config keys:

• blacklisted_strings
• blacklisted_extensions
• blacklisted_paths
• blacklisted_entropy_extensions

Error messages:

• "Blacklisted string %s matched"
• "matchString: Skipping matches containing blacklisted strings"
• "processHsRegexMatch: Skipping matches containing blacklisted strings"

If possible, retain the blacklist_* config keys for backwards compatibility, using them as undocumented aliases for the equivalent exclude_ keys.