fix: Solidity Coding Style Guideline Violations

[NicolasRampoldi]

Description

• Following the Solidity Style Guide wherever possible is advisable, especially when it comes to variable name conventions and code layout.
• This can be consistently enforced across the entire code base by means of an automatic linter, such as Solhint.

Examples

• Variable names should begin lower case. Type declarations (including Contracts) begin upper case.
• Declare modifiers before functions and don’t mix them.