Add memory cache backend for improved scan efficiency

[knqyf263]

Description

Introduce a memory cache backend to scan cache, improving performance for repository, filesystem and SBOM scans.

Current Situation

• File system cache is currently used for all scan types by default
• For repository, filesystem and SBOM scans, this leads to inefficient write-then-delete operations as they don't need cache.

Key Changes

• Implements an in-memory cache backend in addition to filesystem and Redis backends
• Sets memory cache as default for repository, filesystem and SBOM scans
• Eliminates unnecessary disk I/O in these scans

Benefits

• Improved efficiency: Removes redundant write/delete operations
• Faster scans: Reduces I/O operations, especially for repository, filesystem and SBOM scans
• Versatility: Can be used for other scan types when persistent caching isn't needed