feat: port Analysis.Convex.Cone.Basic (#4152)

Co-authored-by: Yury G. Kudryashov <urkud@urkud.name>

Author: mcdoll

Mathlib.lean

@@ -400,6 +400,7 @@ import Mathlib.Analysis.Convex.Body
 import Mathlib.Analysis.Convex.Caratheodory
 import Mathlib.Analysis.Convex.Combination
 import Mathlib.Analysis.Convex.Complex
+import Mathlib.Analysis.Convex.Cone.Basic
 import Mathlib.Analysis.Convex.Contractible
 import Mathlib.Analysis.Convex.Exposed
 import Mathlib.Analysis.Convex.Extrema