feat: add optional value for redaction, with a default of 100

[fr12k]

This commit introduces an optional value for the --redact flag, allowing users to specify the extent of redaction for secrets. The valid range of values is from 0 (no redaction) to 100 (full redaction).

If no value is provided, the default redaction value is set to 100, resulting in complete redaction by replacing the secret with the term 'REDACTED'. This preserves the original behavior of the --redact flag.

Description:

This make it possible now to run gitleaks and only redact the secret with an configureable level.

gitleaks --redact
# equals to
gitleaks --redact=100
# example for 75 % reduction
gitleaks --redact=75

Enable selective secret redaction in gitleaks

This update introduces a new feature to gitleaks, allowing users to specify the level of redaction when running the tool. Previously, the --redact flag only provided a boolean option. With this enhancement, the redaction level can now be configured.

To perform full redaction, use the following command:

gitleaks --redact
# or
gitleaks --redact=100

For partial redaction (e.g., 75% reduction), use the following command:

gitleaks --redact=75

This enhancement provides users with greater flexibility in customizing the redaction level according to their specific needs.

This enhancement maintains backward compatibility, ensuring that the existing usage of gitleaks --redact continues to function as before.

Checklist:

• Does your PR pass tests?
• Have you written new tests for your changes?
• Have you lint your code locally prior to submission?

[ngoduykhanh]

Maybe @zricethezav can take a look at this contribution please 👍

[zricethezav]

Hi @fr12k, sorry for the delay in reviewing this PR. I like it! I think this is a useful feature and would love to include it in the next release. Would you mind resolving the conflicts? Thanks for writing tests too :)