I'm talking about single flours, such as quinoa flour, amaranth flour, and buckwheat flour, not flour blends or hot cereal mixes.
Yes, you can do it. It will taste more like a pudding (not necessarily wheat pudding) than like a cereal. The consistency will depend on the grind size, and can get down to standard starch pudding, or be a bit gritty like semolina pudding.
Most people won't find the taste of a pure flour + water or even flour + milk pudding interesting enough, so you can experiment adding stuff to it. You're only limited by your own imagination.
Yes definitely you can use flour as a breakfast dish. All you need to do is, dry roast the flour a little bit keeping in mind not to burn it. Perfectly roasted flour emanates a special smell(aroma) which is a bit sweet. Thereafter add some water to the flour to make a slurry out of it, alongside you can add some fried potatoes or leftover hash-browns with fried spinach or anything you like which is cooked al dente(just a suggestion) and blend them in the flour(slurry). I'd suggest, cook the slurry for a bit till it reaches the desired form where everything is perfectly blended and in perfect harmony. There you have a nutritious breakfast!
I do lightly brown my gluten free flour, brown rice, sorghum, and millet are my favorites. Then make a slurry as the first answer suggested. The amount of flour to water (or milk) ratio depends on the flour and how thick you like your porridge. Personally I found brown rice to be 2-3Tbsp of browned flour to 1 cup of water, but some of the other flours take more. We like to sweeten ours after it is cooked with a little honey (brown sugar would also work) or your sweetener of choice.