* Replicate poco into base/poco/
* De-register poco submodule
* Build poco from ClickHouse
* Exclude poco from stylecheck
* Exclude poco from whitespace check
* Exclude poco from typo check
* Remove x bit from sources/headers (the style check complained)
* Exclude poco from duplicate include check
* Fix fasttest
* Remove contrib/poco-cmake/*
* Simplify poco build descriptions
* Remove poco stuff not used by ClickHouse
* Glob poco sources
* Exclude poco from clang-tidy
