Add exclusion settings for CloudFormation linting

## Problem

There is currently no way to add an exclusion list for `cfn-lint` or `cfn-guard` rules

## Expected behavior

Please provide the ability to add an exclusion list for `cfn-lint` and `cfn-guard` rules in the settings. The CloudFormation Linter extension does this as shown in the example below:

```json
{
"cfnLint.ignoreRules": [
"I3042",
"I3013",
"W3045",
"E3002",
"E3512",
"E1019",
"E3031",
"W2501"
]
}
```

Start by locating the existing CloudFormation linting settings and the code paths that invoke cfn-lint and cfn-guard. Add settings matching the requested exclusion-list behavior for both tools, then verify that each configured rule is excluded while other rules still run.

Written by the indexing model from the issue text.