Added simple Trie lookup tree which is more tailored to what is needed
in autocomplete implementation, but still has the speed of the
LatinLookupTree that has been used till now. As the implementation
is much simpler it should be more managable and easier fixable.

For now two actions: insert (word) and findSuggestions are supported.
Acttion findSuggestion returns all words in a list for a searched
sub-word, it also fixes fdo#62945.

Change-Id: I63b69c30d28b4e1c465c2122ebc537f7f75a033a