feat: add memory cache backend

[knqyf263]

Description

See #7047 for details

Usage

For repository scans (and filesystem/SBOM), it's used by default now.

$ trivy repo my-repo

For container image scans, you can specify this if you don't need cache.

$ trivy image debian:11 --cache-backend memory

Related issues

• Close Add memory cache backend for improved scan efficiency #7047

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[DmitriyLewen]

LGTM.

Left one improvement