Deprecate SECRET_DETECTION_COMMIT_* options

Description

Gitleaks v8.0.0 removed all --commit* options and instead offered a more flexible --log-opts option which accepts git log options.

Commit related options

Variable	Reason for deprecation
`SECRET_DETECTION_COMMIT_FROM`	Can be replaced by `SECRET_DETECTION_LOG_OPTS`
`SECRET_DETECTION_COMMIT_TO`	Can be replaced by `SECRET_DETECTION_LOG_OPTS`
`SECRET_DETECTION_COMMITS`	Can be replaced by `SECRET_DETECTION_LOG_OPTS`
`SECRET_DETECTION_COMMITS_FILE`	Can be replaced by `SECRET_DETECTION_LOG_OPTS`

These deprecations would reduce the complexity in the analyzer as we are parsing a commits file and generating git log options from that commits file.

Other options that should be deprecated

Variable	Reason for deprecation
`SECRET_DETECTION_ENTROPY_LEVEL`	Entropy only rules are not supported by gitleaks. They caused too many false positives

Tasks

Update documentation
Remove variables
Detect if these variables are provided and print a warning

Edited May 17, 2022 by Zach Rice