New rule: StrUtils should be preferred over 'Copy'

### Prerequisites

- [X] This rule has not already been suggested.
- [X] This should be a new rule, not an improvement to an existing rule.
- [X] This rule would be generally useful, not specific to my code or setup.

### Suggested rule title

Should use 'LeftStr' instead of 'Copy' from start

### Rule description

Using `Copy(Text, 1, Count)` is the equivalent of using `LeftStr(Text, Count)` but impacts readability and making the intention harder to understand. Using `LeftStr` conveys intention better.

### Rationale

Seeing many `Copy` used in different context makes it harder to understand the intention of its usage. By removing a sizeable chunk of generic `Copy(Text, 1, Count)`, it makes it easier to focus on where other usage of `Copy` does matter.