[Feature] Support to use third-part cuelang packages when write x-definition.

[leejanee]

Is your feature request related to a problem? Please describe.

Support to use third-part cuelang packages when write x-definition. Because there are often the following demands:

1. share user-defined packages.
2. generate cuelang packages from golang code.

At the same time, processing packages will cause performance degradation on server side. Processing packages is more elegant on the client side.

Describe the solution you'd like

kubevela should embrace cuelang packages manage.

New definition on client side as follows:

import "user.io/common/deploy"

parameter: {
    image: string
    replicas: int
}

up: deploy.#Workload & {image: parameter.image, replicas: parameter.replicas}

user.io/common/deploy is a user-defined package.

Describe alternatives you've considered

If you want to use kubernetes api define in kubevela definition. You can use cue get go to generate third-part cuelang packages

Definition will be as follows:

import (
    "k8s.io/api/core"
    "vela/op"
)

apply: op.#Apply & core.#Pod 
apply: {
    spec: image: "busybox"
}

Additional context