[C++/Python] Remove defunct conda recipes

[asfimport]

These recipes will be maintained outside of the ASF git repo (e.g. in conda-forge)

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

_{Note: This issue was originally created as ARROW-408. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
PR: #231

[asfimport]

Uwe Korn / @xhochy:
Issue resolved by pull request 231
#231