arrow

ARROW-1912: [Website] Add committer affiliations and roles to website

cc @jacques-n

Author: Wes McKinney <wes.mckinney@twosigma.com>

Closes #1596 from wesm/ARROW-1912 and squashes the following commits:

ed30ecd1 [Wes McKinney] Add LLC designation for Uwe
2fb8d892 [Wes McKinney] Add committer affiliations to website