nostr : book: add tags python examples

* Tag creation and parsing

* Accessing and logical tests

Closes https://github.com/rust-nostr/nostr/pull/487

Signed-off-by: Yuki Kishimoto

https://github.com/rust-nostr/nostr/commit/c8e3d5b4d27ba99a02261354961ee2026316b7b2