Allow wildcard strings search

Search 'inter*', it returns all the messages containing
string starts with 'inter' like interwiki, internal, internally.
Search 'inter*wiki*', there is no support for * in the middle
of search strings and ignores all the letters after the first * found,
therefore, it is equivalent to search 'inter*'.

Used Edge-n-grams only at the index time and standard analyzer at
the search time. For search string like 'Returns thumb*', it returns
all the messages containing returns or thumb*.

Provides highlighter for prefix matching.

Bug: T100345
Change-Id: I309d6d7d717c9d2e09c7411b2c098ff3ab59e016