Integrate Conan Documentation

Conan is currently described in an own section "Building with Conan". Adaptions according to discussion in the requirement refinement meeting on 08.09.2021:

• Describe relevant steps using Conan within the section "Installing Prerequisites" in a "copy-and-paste" manner
• Move instructions to manually build the dependencies to "Further Guidance"
• Potentially add more explanation on Conan in "Further Guidance"

Depends on !38 (merged) and Merge of branch "2-ci-setup-windows"