Slogan of envd

[gaocegege]

Now we use Development environment for ML as the slogan. We did not discuss it further, thus I think we can have a better slogan with the help of the community 🎉

BTW, the name envd comes from this issue #2

Besides this, we also need a logo #326

[terrytangyuan]

Some ideas:

1. Build it once and deploy it everywhere.
2. Out-of-box data science workbench for everyone.