Restructure storage of lexicons

[akolonin]

At the moment, lexicons are stored in the root:
lexicon_english.txt
lexicon_negative_english.txt
lexicon_negative_russian.txt
lexicon_positive_english.txt
lexicon_positive_russian.txt
lexicon_rude_english.txt
lexicon_rude_russian.txt
lexicon_russian.txt

We want to change it, along with adding support for cognitive distortions, to be like this:

data
  dict
    en
       lexicon.txt
       negative.txt
       positive.txt
       rude.txt
       mentalfiltering.txt
       magnification.txt
       ...
    ru
       lexicon.txt
       negative.txt
       positive.txt
       rude.txt
    zh