Add support for simple aggregate functions

[kbennoune]

Description

Simple Aggregate Functions let you use some aggregate functions with SummingMergeTree and AggregatingMergeTree materialized views without having to use State and Merge suffixes.

e.g.

    create_table :mv_target, id: false, options: "SummingMergeTree((total_count_sum, last_timestamp)) do |t|
      t.integer :account_id, limit: 8, null: false
      t.integer :total_count_sum
      t.column :last_timestamp, "SimpleAggregateFunction(anyLast,DateTime64)", null: false
    end