v4.4.0

Updated the CI, added guidelines for collaboration Modified subprojects (since v4.3.0): cfa/cfa cfa/cfa-analysis cfa/cfa-cli common/analysis common/common common/core frontends/c-frontend frontends/chc-frontend solver/solver solver/solver-smtlib solver/solver-smtlib-cli solver/solver-z3 sts/sts sts/sts-analysis sts/sts-cli xcfa/cat xcfa/xcfa xcfa/xcfa-analysis xcfa/xcfa-cli xsts/xsts xsts/xsts-analysis xsts/xsts-cli xta/xta xta/xta-analysis xta/xta-cli