feat: add higher-order component helper for vuelidate

[shentao]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the dev branch for v1.x (or to a previous version branch), not the master branch
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• All tests are passing: https://github.com/vuelidate/vuelidate/blob/master/.github/CONTRIBUTING.md#development-setup
• New/updated tests are included

If adding a new feature, the PR's description includes:

A helper higher-order component that should make it possible to put validation rules inside the template easily instead of defining those in the wrapper component. Example usage in test-project:

// _TextInput is an input component
const TextInput = withVuelidate(_TextInput)

// in template
<TextInput v-model="value" :rules="{ required }" />

Sad part: Works but there is an infinitely recursive thing going on which makes everything super slow.

Other information:

[dobromir-hristov]

@shentao I looked into this and if the rules are defined as computed or data properties and passed to the WithVuelidate wrapped component, there is no recursion issue. But applied on the component itself, it just does not work

[shentao]

Uh... Any idea how to solve that?

[dobromir-hristov]

I think it's just a problem with applying a watcher to a reactive prop, defined in the template.
I did something similar today, but with array.reverse in the template. Threw the same error, fixed it by creating a computed property.

[shentao]

Could this be a vue 2.x limitation?

[dobromir-hristov]

I think it's in both versions.