move request data from header to body in searcher

add tokens counter utility

update b+tree flushing policy and set containers to autorestart

fix error when page have no title

add debug info for searcher

change indexing order

add error handling

add metrics to cache usage

add caching to b+tree

add delete function to map

fix bug: error when search very big value in db

fix static config

add porter's stemmer algo and change proc start in docker container

move tokenizer and db logic to corresponding Userver components

change indexer behaviour from request-response to standalone component

update crawler docker build file

change crawler content fetching behavior

add frontend

update deploy schema