Use clippy as linter for Rust code

[matjazv]

Description

Project will be using Clippy as linter for Rust code.

• clippy.toml file needs to be created with following attributes:

# cyclomatic complexity is not always useful
cognitive-complexity-threshold = 100
# types are used for safety encoding
type-complexity-threshold = 10000
# we won’t allow too many function arguments
too-many-arguments-threshold = 13

• GitHub action needs to be created to check Clippy warnings when a PR is created and when a PR is merged

Acceptance Criteria

• clippy.toml file exists in project's root directory
• GitHub action is created