Various docker caching, CLI and config validation improvements

[spillai]

• Improved pip/conda/apt caching with docker build mount targets
• Fix python version parsing:
  • For python versions like 3.10, versions were being cast from float to
    string, leading to "3.1" builds.
  • Added tests for malformed python version
  • Improved python validation for version strings
• Fixes for CLI -b, -p flags and jinja template for non-interactive mode builds
• Support skip-base-builds and target builds in CLI
• improved pydantic config validation with forbidden extras