Add a feature to scan binary files content using their printable strings

[gg-mhacks]

Is your feature request related to a problem? Please describe.

As a user, I would like to be able to scan the content of a binary file, it might be possible through its printable strings by using string.printable python method

Here is my test using strings unix utility

$ ggshield secret scan path ./cppcreds
Scanning Path... ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 1 files scanned out of 1 0:00:00

No secrets have been found

$ strings ./cppcreds > strings_cppcreds
$ ggshield secret scan path strings_cppcreds
Scanning Path... ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 1 files scanned out of 1 0:00:00

secrets-engine-version: 2.77.0

🛡️  ⚔️  🛡️  1 incident has been found in file /home/*/__tmp/strings_cppcreds

>>> Incident 1(Secrets detection): AWS Keys (Validity: Invalid)  (Ignore with SHA: e019aff773f5746c91c7eb8660c4542029e44144bdbc80cb607130d431a2664d) (1 occurrence)
 45 | PTE1
 46 | u+UH
 47 | AKIA************5F67
      |_____client_id____|
 48 | Z7MB/eU**************************ZOcphH2
      |_____________client_secret____________|
 49 | aws_access_key_id: 
 50 |   aws_secret_access_key:

Describe the solution you'd like

There should be a way to scan strings contained in binaries.

Describe alternatives you've considered

Currently, we need to extract printable strings into a file and then launch a scan over it to achieve this goal.