Add support for suppressions.yaml

Precursors:

- https://github.com/Azure/azure-rest-api-specs/issues/40837
- https://github.com/Azure/azure-rest-api-specs/issues/40849

To workaround problems like this:

- https://github.com/Azure/avocado/issues/150

We should add support for suppressing Avocado errors in `suppresions.yaml`. An example suppression might look like:

```yaml
- tool: SwaggerAvocado
rules: [MISSING_APIS_IN_DEFAULT_TAG]
paths: [readme.md]
sub-paths:
- "/subscriptions/{}/providers/microsoft.foo/bar/{}/providers/microsoft.foo/baz"
- "/subscriptions/{}/providers/microsoft.foo/bar/{}/providers/microsoft.foo/baz/{}"
```

Supporting this would require adding option `subPaths` alongside `paths` in the suppression interface:

```js
export interface Suppression {
tool: string;
if?: string;
paths: string[];
rules?: string[];
subPaths?: string[]; // new
subRules?: string[];
reason: string;
}
```

Common rules to suppress:
- MISSING_APIS_IN_DEFAULT_TAG
- Allowed if APIs were approved for removal/deprecation
- MULTIPLE_API_VERSION
- Small number of specs still don't have aligned API versions. Better to suppress once in suppressions.yaml, than suppress in every future PR.