Asset copying does not respect hidden entities

[Dave Stewart]

Description

Nuxt Content supports _dir, ignored and partial entities but Nuxt Content Assets doesn't respect these rule.

When it scans for assets, hidden and ignored files are copied.

Expected

Nuxt Content Assets should only copy non-ignored assets.

Notes

 [content-assets] Copied "content" assets:

   - 1.guide/_dir.yml
   - 1.guide/1.getting-started/_dir.yml
   - 1.guide/2.model/_dir.yml
   - 1.guide/3.relationships/_dir.yml
   - 1.guide/4.repository/_dir.yml
   - 1.guide/5.nuxt/_dir.yml
   - 2.api/_dir.yml
   - 2.api/4.repository/_dir.yml
   - 2.api/3.query/_dir.yml
   - 2.api/1.composables/_dir.yml
   - 2.api/2.model/_dir.yml
   - 2.api/2.model/1.options/1.fields-attributes/_dir.yml
   - 2.api/2.model/1.options/2.fields-relations/_dir.yml