Fix docs for Lazy database

[RFC] Introduce uniqCombined64() to get sane results for cardinality > UINT_MAX

Do not use more then 98K of memory for uniqCombined*

Return SparseHashed name (system.dictionaries:type) for the sparse_hashed layout

Grammatical mistake

Added function `getMacro`

Rename yandex → ClickHouse

Dictionaries ddl parser

Due to tons of rebasing this bit had been forgotten.

Refs: 420089c3 ("Add new dictionary layout (sparse_hashed) that is more memory efficient")

Serialize Null Fields correctly in DataTypeNullable.

Make sure dh_clean not touch potential source files.

uniqCombined() uses hashtable for medium cardinality, and since
HashTable resize by the power of 2 (well actually HashTableGrower grows
double by the power of 2, hence HashTableGrower::increaseSize() should
be overwritten to change this), with 1<<13 (default for uniqCombined)
and UInt64 HashValueType, the HashTable will takes:

  getBufferSizeInBytes() == 131072

While it should be not greater then sizeof(HLL) ~= 98K, so reduce the
maximum cardinality for hashtable to 1<<12 with UInt64 HashValueType and
to 1<13 with UInt32, overwrite HashTableGrower::increaseSize() and cover
this using max_memory_usage.

Refs: https://github.com/ClickHouse/ClickHouse/pull/7221#issuecomment-539672742

v2: cover uniqCombined() with non-default K

added groupBitmapAnd, groupBitmapOr, groupBitmapXor

Include Field.h and FieldVisitor.h into fewer files.

Lazy Database

By default uniqCombined() uses 32-bit hash for all types except String,
so this means that you cannot use uniqCombined() with i.e UInt64 and
cardinality > UINT_MAX, although you can use uniqCombined(toString())
and this will lead to 64-bit hash, but will not have good performance.

So uniqCombined64() had been introduced to fix this.

Requires: #7213

Fix uniqCombined() result for >UINT_MAX values (return UInt64 to avoid overflow)

Merging "Optimize empty IN subquery and empty INNER/RIGHT JOIN"