Extends the name search feature to use additional, more relaxed
matching methods, and to allow searching into configurable additional
record fields.

The name search is the lookup feature to select a related record.
For example, selecting a Customer on a new Sales order.

For example, typing "john brown" doesn't match "John M. Brown".
The relaxed search also looks up for records containing all the words,
so "John M. Brown" would be a match.
It also tolerates words in a different order, so searching
for "brown john" also works.

.. figure:: https://raw.githubusercontent.com/OCA/server-tools/11.0/base_name_search_improved/images/image0.png

Additionally, an Administrator can configure other fields to also lookup into.
For example, Customers could be additionally searched by City or Phone number.

.. figure:: https://raw.githubusercontent.com/OCA/server-tools/11.0/base_name_search_improved/images/image2.png

How it works:

Regular name search is performed, and the additional search logic is only
triggered if not enough results are found.
This way, no overhead is added on searches that would normally yield results.

But if not enough results are found, then additional search methods are tried.
The specific methods used are:

- Try regular search on each of the additional fields
- Try ordered word search on each of the search fields
- Try unordered word search on each of the search fields

All results found are presented in that order,
hopefully presenting them in order of relevance.
