Manually specify price for created asset

[giurgiur99]

We need to change the behaviour of the createAsset function, because the stats price should be updated by node, when the ddo gets indexed, not retrieved from ddo object (because ddo structure might change as it is happening for indexedMetadata, value was previously used) before creating the nft + datatoken + pricing schema.

This function should have another parameter for price, in case the asset is priced, otherwise it should have a dispenser attached.