Correctly report indices and aliases

[mpeychich]

Improve the reporting on indices and aliases that match index naming.

Before

Indices created via Chewy without a suffix would fail to report themselves as an index or alias for the Chewy index.

DummyIndex.create! # => {'acknowledged' => true}
DummyIndex.indexes # => []
DummyIndex.aliases # => []

Indices created via Chewy with a suffix would correctly report the suffixed index but would fail to report the alias

DummyIndex.create!('2013') # => {'acknowledged' => true}
DummyIndex.indexes # => ['dummies_2013']
DummyIndex.aliases # => []

After

Indices created via Chewy without a suffix will correctly report themselves as an index.

DummyIndex.create!
DummyIndex.indexes # => ['dummies']
DummyIndex.aliases # => []

Indices created via Chewy with a suffix will correctly report the alias

DummyIndex.create!('2013') # => {'acknowledged' => true}
DummyIndex.indexes # => ['dummies_2013']
DummyIndex.aliases # => ['dummies']

[dalthon]

It was rebased at #757 and some details were changed in order to avoid some false positives on indexes when two distinct classes are named with containing names.

It is waiting a little to merge, just to make sure that breaking changes introduced will not affect other stuff