Zaz, Agreement that you received now is actually an offer letter. You will be signing the employment contract once you are in Qatar and have completed all formalities such as your medical checkup, residence permit etc. If you want to negotiate the terms, you should do it now and if they agree, get the revised offer letter.  You should certainly ask them to specify that they will be providing you accommodation.

You can find a copy of Qatar labour law online, go through that, you will find answers to many questions you might have in mind.