WIP Normalize for diacritics

PR branch for #729

Tasks to do
- [x] unicode normalization client side for page search with unorm and xregexp
- [x] unicode normalization for ES queries, setting up analyzers
- [x] unicode normalization for backend stream
- [x] add tests
- [ ] launch a showcase dokku instance 
Yes, I agree that this is our ultimate goal. Currently ASCII folding is used only to be compatible with the client side.
But, as I understand, de facto @nickstenning and @tilgovi supports the idea that the client side search and backend search will work differently from now on.

Changing the analyzers.