Sensitive line anonymization consistency

[sfraint]

A given sensitive item (from a config line known to contain sensitive info) is anonymized based on the number of the sensitive items encountered before it. This means inserting a new sensitive line and re-anonmyzing a file may result in different anonymized values for other sensitive items in that file.

Could apply a similar idea to what is now used for IP address anonymization (hash of original value + salt, so new anon values would depend solely on the salt and unanonymized sensitive item).