feat: add missing createRoles association method for HasMany relationship

[sakupan102]

Pull Request Checklist

• Have you added new tests to prevent regressions?
• If a documentation update is necessary, have you opened a PR to the documentation repository?
• Did you update the typescript typings accordingly (if applicable)?
• Does the description below contain a link to an existing issue (Closes #[issue]) or a description of the issue you are solving?
• Does the name of your PR follow our conventions?

Description of Changes

• Added new method createMultiple to create multiple associated instances.
  Example use case:

class Article extends Model:
  declare: id: number;
  @HasMany(() => Label, 'articleId')
  declare createLabels: HasManyCreateAssociationMixin<Label>
class Label extends Model:
  declare id: number;
  declare articleId: number

const article = await Article.create();
const labels = await article.createLabels([{id: 100}, {id: 200}])
// created two instances

this PR closes #11372

[ephys]

Thank you for your PR. This would be a nice addition

---

Don't forget to add the following:

• Typing test
• Integration test

[ephys]

instead of copying the code, create should call createMultiple

[ephys]

Suggested change

	// TODO: add createMultiple association method for BelongsTo relationship
	// TODO: add createMultiple association method for BelongsToMany relationship

Ideally this should be done in the same PR, as it now declares it as being available

[ephys]

Don't forget to add the HasManyCreateAssociationsMixin type