ranker: models addition

* Adds model for rnkSELFCITEDICT and rnkCITATIONLOG tables.

* Fixes a typo in RnkMETHOD model.

Signed-off-by: Mateusz Susik <mateuszsusik@gmail.com>
authorids: new SQLAlchemy models. (adresses #1790)

* Adds SQLAlchemy model for aidDENSEINDEX and aidINVERTEDLISTS tables.

* Refactors the indentations

Signed-off-by: Mateusz Susik <mateuszsusik@gmail.com>
authorlist: initial release. (fixes #1891)

* Adds new module inside /invenio/invenio/modules for authorlist

* Adds SQLAlchemy models for 6 new tables.

Signed-off-by: Mateusz Susik <mateuszsusik@gmail.com>