bug: config file generated by --generate-default-config contains removed and deprecated flags

[DmitriyLewen]

Description

Trivy includes all flags into config file when using --generate-default-config command.
But Trivy returns error for this config file:

➜ trivy image   
2024-12-03T12:44:48-07:00       INFO    Loaded  file_path="trivy.yaml"
2024-12-03T12:44:48-07:00       ERROR   "--reset" was removed. Use "trivy clean --all" instead.
2024-12-03T12:44:48-07:00       FATAL   Fatal error     flag error: db flag error: unable to parse flag: removed flag ("--reset")

We need to exclude removed and obsolete flags from the generated configuration file.

Discussed in #8035