Use inputs as objects when creating package policies

[jsoriano]

elastic-package is using a legacy arrays-based format when creating package policies (around here).

According to the documentation, this format is deprecated and a new format based on objects should be used.

We should check since what version this new format exists, in case we need to support both formats for old versions.

Update: elastic-package is actually using both formats, there is a type kibana.PackageDataStream that uses the arrays format, while the kibana.PackagePolicy uses the object format. They have equivalent methods that at the end use the same /package_policies endpoints. See for example:

• elastic-package/internal/kibana/policies.go

  Line 242 in e84244e

  func (c *Client) AddPackageDataStreamToPolicy(ctx context.Context, r PackageDataStream) error {

• elastic-package/internal/kibana/policies.go

  Line 287 in e84244e

  func (c *Client) CreatePackagePolicy(ctx context.Context, p PackagePolicy) (*PackagePolicy, error) {

kibana.PackageDataStream type and related helpers should be removed in favor of kibana.PackagePolicy.