global: update for ES7

[pamfilos]

We should update to ES7 to be ready for the move to K8 and ESoD.

In general, we should have most packages ready (invenio-search, Invenio-records-rest, etc), but we should:

• [x] investigate what else might be needed
• [x] update mappings

[ParthS007]

After investigation, the task can be broken in multiple steps:

• [x] 1. Update the ES version to 7.

• [x] 2. See the warnings and error in logs that are version related and not.

• [x] 3. Update mappings, filters and post filters and related invenio libraries.

• [x] 4. Repeat 2 and 3 until everything is ok.

what do you think?