Implementation of finite reflection groups

[stumpc5]

This patch implements reflection groups to work with finite (crystallographic, real, complex) reflection groups. It is based on the GAP3 package chevie which is now an experimental package, see #20107.

sage: W = ReflectionGroup(['A',2],5,23); W
Reducible complex reflection group of rank 7 and type A2 x ST5 x H3
sage: W.irreducible_components()
[Irreducible real reflection group of rank 2 and type A2,
 Irreducible complex reflection group of rank 2 and type ST5,
 Irreducible real reflection group of rank 3 and type H3]

CC: @sagetrac-vripoll @kevindilks @simon-king-jena @sagetrac-jmichel @hivert

Component: combinatorics

Keywords: reflection group, days49, days64.5, days80

Author: Christian Stump, Frédéric Chapoton, Nicolas M. Thiéry, Travis Scrimshaw

Branch/Commit: 0b6d895

Reviewer: Christian Stump, Frédéric Chapoton, Nicolas M. Thiéry, Vivien Ripoll, Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/11187

[stumpc5]

comment:2

Apply only trac_11187-finite_reflection_groups-cs.patch

[stumpc5]

comment:3

Apply only trac_11187-finite_reflection_groups-cs.patch

[stumpc5]

Dependencies: 8327

[stumpc5]

Description changed:

--- 
+++ 
@@ -5,5 +5,3 @@
 ```
 
 to work with finite (crystallographic, real, complex) reflection groups. It uses the data from GAP3/chevie.
-
-Depends on #8327.

[stumpc5]

comment:6

Apply only trac_11187-finite_reflection_groups-cs.patch

[stumpc5]

Changed dependencies from 8327 to #8327