Support filter by file with file pattern and literal configuration

[JamieSlome]

Background

GitProxy currently supports commit message, commit diff and commit e-mail domain scanning. A common use case that is not supported is file name filtering and scanning.

Vision 🪄

"message": {
  "block": {
    "literals": ["xlsx", "csv"],
    "patterns": [".*.txt"]
  }
},

### Tasks