[docs] Use full text of the code of conduct (#16417)
[docs] Use full text of the code of conduct (#16417)

While the current tongue in cheek "abridged" version has served us well, now that the project has matured and the community has grown, it seems appropriate to reinstate the full version.
mui-org/material-ui,oliviertassinari/material-ui,callemall/material-ui,lgollut/material-ui,kybarg/material-ui,rscnt/material-ui,kybarg/material-ui,rscnt/material-ui,kybarg/material-ui,callemall/material-ui,oliviertassinari/material-ui,mbrookes/material-ui,oliviertassinari/material-ui,callemall/material-ui,mui-org/material-ui,mbrookes/material-ui,mbrookes/material-ui,kybarg/material-ui,callemall/material-ui,mui-org/material-ui,rscnt/material-ui