Create the asset packs client methods

To complete this task the following APIs should be queryable from the client:
- PUT: `/assetPacks/${remotePack.id}`
- POST: `/assetPacks/${asset.assetPackId}/assets/${asset.id}/files`
- POST: `/assetPacks/${assetPack.id}/thumbnail`
- GET: `/assetPacks` to default and to an owner.
- DELETE: `/assetPacks/${assetPack.id}`

Take into consideration the following:
- The types that currently live in the builder UI must be moved to either `@dcl/schemas` or the client itself.
- The fromX and toX methods must be included in the client. They don't need to be exported.