Adding type checking and code style enforcement to CI

[arnasbr]

Added mypy for type checking, black for code style.

• Fixed type mismatches
• Fixed some deprecated function calls

[arnasbr]

no clue why it's not ignoring these files, it works perfectly fine locally.

[mypy]
ignore_missing_imports = True
exclude = ^(traveltimepy/proto/|build/|venv/)$

it does take the ignore_missing_imports rule tho, so it's using the config correctly. I'll continue tomorrow

[danielnaumau]

Looks great, thank you !