Added histogram aggregate function

Why it matters

The histogram aggregate function allows users to compute histograms directly within ClickHouse queries. This enables efficient aggregation and analysis of data distributions without external processing, providing valuable insights into the frequency distribution of values.

How to use it

Use the histogram aggregate function in your queries by applying it to a column of numeric data. For example: SELECT histogram(column_name) FROM table_name; to compute the histogram of values in column_name.