implement: src/control_flow -- conditionals, match, if-let, while-let

[BryanChasko]

topic: control flow

rust mirror of conditionals. rust's match is exhaustive -- compiler enforces all cases.

concepts to demonstrate

• if/else with type-consistent arms
• match on integers, enums, tuples
• if let for Option unwrapping
• while let for streaming data
• match guards

patriots theme

match on game state: quarter, score differential, field position.
if let Some(result) = game_log.get(week) pattern.

file

src/control_flow/game_state.rs

reference

python mirror: basic_match_name_input_NFL_legends.py