* Some improvements for introduction/performance.md

* Minor improvements for example_datasets

* Add website/package-lock.json to .gitignore

* YT paragraph was badly outdated and there is no real reason to write a new one

* Use weird introduction article as a starting point for F.A.Q.

* Some refactoring of first half of ya_metrika_task.md

* minor

* Weird docs footer bugfix

* Forgotten redirect

* h/v scrollbars same size in docs

* CLICKHOUSE-3831: introduce security changelog

* A bit more narrow tables on docs front page

allow empty parts after merge for Summing, Collapsing and VersionedCollapsing engines [#CLICKHOUSE-3879]

* CLICKHOUSE-3863: Add HTTPS support for interserver replication

* CLICKHOUSE-3863: Add more convinient exception message

* Fix summingmergetree docs

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using unixodbc as submodule [#CLICKHOUSE-3]

* Using internal mariadb-client library [#CLICKHOUSE-2]

* Using internal mariadb-client library [#CLICKHOUSE-2]

* Using internal mariadb-client library [#CLICKHOUSE-2]

* Using internal mariadb-client library [#CLICKHOUSE-2]

* Using internal mariadb-client library [#CLICKHOUSE-2]

* Some improvements for introduction/performance.md

* Minor improvements for example_datasets

* Add website/package-lock.json to .gitignore

* YT paragraph was badly outdated and there is no real reason to write a new one

* Use weird introduction article as a starting point for F.A.Q.

* Some refactoring of first half of ya_metrika_task.md

* minor

* Weird docs footer bugfix

* WIP on content of distinctive_features.md

* WIP on content of features_considered_disadvantages.md

- Descriptions for functons: arrayResize, multiIf, getSizeOfEnumType, toColumnTypeName, dumpColumnStructure, defaultValueOfArgumentType, indexHint, replicate.
- Enum description is updated

* Macos: fix mysql link

* Macos: Fix mysql include

* doc

* Additional .gitignore entries

* Merge a bunch of small articles about system tables into single one

* Merge a bunch of small articles about formats into single one

* Adapt table with formats to English docs too

* Add SPb meetup link to main page

* Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles

* Merge MacOS.md into build_osx.md

* Move Data types higher in ToC

* Publish changelog on website alongside documentation

* Few fixes for en/table_engines/file.md

* Use smaller header sizes in changelogs

* Group up table engines inside ToC

* Move table engines out of top level too

* Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye.

* Move stuff that is part of query language into respective folder

* Move table functions lower in ToC

* Lost redirects.txt update

* Do not rely on comments in yaml + fix few ru titles

* Extract major parts of queries.md into separate articles

* queries.md has been supposed to be removed

* Fix weird translation

* Fix a bunch of links

* There is only table of contents left

* "Query language" is actually part of SQL abbreviation

* Change filename in README.md too

* fix mistype

* s/formats\/interfaces/interfaces\/formats/g

* Remove extra clarification from header as it was too verbose, probably making it a bit more confusing

* Empty article was supposed to be hidden

* At least change incorrect title

* Move special links to the bottom of nav and slightly highlight them

* Skip hidden pages in bottom navigation too

* Make front page of documentation to be part of Introduction

* Make tables in introduction somewhat readable + move abbreviation definitions earlier

* Some introduction text refactoring

* Some docs introduction refactoring

* Use admonitions instead of divs

* Additional .gitignore

* Treat .gif as images too

* Clarify ToC item