Added dynamic keyword and Aggregate functions

[SadiHassan]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Below improvements are added:

1. dynamic keyword
2. array_index_of
3. array_length
4. array_sum
   ...

Information about CI checks: https://clickhouse.com/docs/en/development/continuous-integration/

[kashwy]

the above code does not take the advantage of the output of dynamic and the retrieve converted argument. the array can be a result of other functions , for example : parse_jsion can return array also.
so this function can be simplified as:

bool ArrayIndexOf::convertImpl(String &out,IParser::Pos &pos)
{
    String fn_name = getKQLFunctionName(pos);

    if (fn_name.empty())
        return false;

    ++pos;
    String array = getConvertedArgument(fn_name, pos);
    ++pos;
    const auto needle = getConvertedArgument(fn_name, pos);
    out = "minus(indexOf(" + array + ", " + needle + ") , 1)";
  
    return true;
}

the array will be handle by other function and retrieved by getConvertedArgument

[kashwy]

removed unnecessary comment

[SadiHassan]

submitted a new PR after merging changes.