Improve documentation

[R1kaB3rN]

See #202 (comment) for context.

[FireLemons]

Yeah I just tried to install it on regular ubuntu using the readme. Spent a few minutes learning about why pip is warning me that I have an "externally-managed-environment". Then installed hatchling a few times which was pretty hard on linux for some reason.

only for make to keep telling me it can't find hatchling.build

Then I google for instructions that someone else may have made for installation on ubuntu. Fortunately, the releases page appears in the search results. So I go download the one marked ubuntu and it contains 2 .deb files so I try to install umu-launcher_1.1.3-1_all.deb but apparently I need both and the other package has to be installed first.

Sometimes I don't read documentation very carefully and miss a few steps so maybe I missed an alternate set of instructions telling me about the releases.