commits: allow tag commit translation to be skipped for faster commit fetching in big chunks.

search: added narrow result links for global search.

redis: add logging about lock acquire, this should help in case of locked row debugging

spelling: fixed usefull -> useful

auth: simplified auth-token matching code.

api: forbid commenting on closed PR

api: add cache for fts index builder call that returns file tree. This is often re-used and should return unchanged state fast

scm: optimized get_nodes function. - don't calculate size (it uses content which can be *big*) if it's not required.

api: expose new functions for FTS - vcs: added special md5 calculation that doesn't use content cache for more memory efficient md5 calculation.

git: use rev-list for fetching last commit data inc ase of single commit. It's faster that using git log