Remove attachment base64 data after indexing

[viljasenville]

Sometimes it's not necessary to store the original attachment data (as base64) into Elasticsearch index after the actual content is indexed. The original attachment is available as Episerver blob.

It should be possible to add the following processor to attachment pipeline definition:
"remove": {
"field": "_attachmentdata"
}

It would be nice to have configuration value to choose whether the raw data is saved or not.