allow no-invalid-link-text to be configured for custom link component names

[fivetanley]

Right now, the no-invalid-link-text rule checks for invalid link text on <LinkTo> and <a> tags. It would be great if we could allow a custom option to the config for tag names, so that developers using custom/wrapper components could specify additional component invocations to check.

For example, say a developer has an ExternalLink component that they use to consistently style links leading away from the application. We would still want those links to have more meaningful text than "learn more"/etc.

Right now, the rule passes for the following:

<ExternalLink @href={{this.externalLink}}>Learn more</ExternalLink>

We would want the above code to fail the no-invalid-link-text check.

The config could look something like this:

// .template-lintrc.js

module.exports = {
  extends: 'recommended',
  rules: {
    'no-invalid-link-text': {
      additionalTags: ['ExternalLink']
    }
  }
};