Add keepalive_request, hostname_lookups, start_servers, server_limit, max_clients, max_request_per_child to the template and class

Hi,

I've keepalive_request, hostname_lookups, start_servers, server_limit, max_clients, max_request_per_child to the template and class.

Endeed, I think we must use more tunning directive in this puppet module to configure apache. This directivres are writed with defaults values.

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