Remove 'RESERVED' constant no longer used.

This was used back when we supported wildcard-style settings, such as:

    grok { somefield => somepattern }

But we don't support this anymore.
Remove old queue setting support.
Remove 'region' setting support (region_endpoint is the correct way now)
Remove 'pattern' support
Remove support for 'format' setting.
Remove 'name' setting support
Fix tests that relied on now-removed (was deprecated) settings.
Fix specs that failed after removing some old/deprecated things.

The tests haven't changed, just the correctness of how they create
plugins (type, tags, etc are gone from filters, for example)
Fix more tests broke during this big deprecation-removal sweep