elasticsearch 7.x compatability (#576)

* es_mapping: update turning off dynamic mappings

they changed it in 6.x

https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic.html
https://github.com/elastic/elasticsearch/pull/25734

* es_mapping: remove _all field

deprecated in 6.0 anyway

* es_mapping.yml: fix deprecated mapping type

https://www.elastic.co/guide/en/elasticsearch/reference/6.7/removal-of-types.html#_schedule_for_removal_of_mapping_types

it gives a really unhelpful error otherwise, oof.

* es: fix remaining 7.xisms

the enabled: false apparently only applies to
"object" fields now, need index: false

and the _type got removed everywhere. Seems to work now.

* Fix weird offset error with word_delimiter_graph

yet another es7-ism i guess

* Fix warning and some app stuff for ES 7.x

Co-authored-by: Arylide <Arylide@users.noreply.github.com>

import_to_es.py

@@ -34,7 +34,6 @@ def pad_bytes(in_bytes, size):
 def mk_es(t, index_name):
     return {
         "_id": t.id,
-        "_type": "torrent",
         "_index": index_name,
         "_source": {
             # we're also indexing the id as a number so you can