Introduce session setup

[ranaalotaibiMS]

This PR introduces functionality for configuring a session by executing predefined statements before the benchmark execution begins. Users should specify the file containing these statements within the tag <sessionsetupfile> </sessionsetupfile> in the benchmarks' config files. CC: @bpkroth

For example,

<?xml version="1.0"?>
<parameters>

    <!-- Connection details -->
    <type>sqlserver</type>
...
    <!-- Session setup statements file -->
    <sessionsetupfile>config/sqlserver/session_setup_sqlserver_cmds_example.sql</sessionsetupfile>
...