plf_stack: add version 1.64

[toge]

Specify library name and version: plf_stack/*

• add version 1.64
• use add_subdirectory in test_v1_package

---

• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 1 (e7aeea290c21a466759cf1fdcf96338ce97ff571):

• plf_stack/1.63@:
  All packages built successfully! (All logs)

• plf_stack/1.60@:
  All packages built successfully! (All logs)

• plf_stack/1.64@:
  All packages built successfully! (All logs)