New rule: Attribute groups should only contain one attribute

### 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

Attribute groups should only contain one attribute

### Rule description

This rule would detect instances of multiple attributes within the same square brackets (e.g. `[Foo, Bar]`).

```delphi
type
[Foo, Bar('test')] // Noncompliant
TMyClass = class(TObject)
public
[Foo]
[Bar('test')] // Compliant
procedure Baz;
end;
```

### Rationale

Having multiple attributes combined under a single square brackets is confusing, difficult to read, and error-prone. It's not immediately clear that there are multiple attributes applied, instead of a single attribute with constructor arguments.