Improve results sorting

[alvarogzp]

Currently, this is the sorting order:

• exact zone name match
• exact country code match
• exact match on any other field
• query starts with any field
• query contains any field

The 3 latests groups, as they are ones that more number of result zones tend to produce, can have its results sorted inside them by some kind of relevance algorithm.

We can use #8 to sort results by use, either personal use and global use.