A lot of ambiguities due to too general `rand`signatures

还没有人认领这个 Issue。

We are still using this quite heavily in Oscar land, but after playing around with https://github.com/JuliaTesting/Aqua.jl (which helps detecting method ambiguities), I noticed that RandomExtensions.jl leads to a lot of method ambiguities. For example, the methods
```
rand(X, ::Type{Tuple}, n::Integer)
@ RandomExtensions ~/.julia/packages/RandomExtensions/qAD6J/src/containers.jl:53
rand(X, t::Type{<:Array}, dims::Integer...)
@ RandomExtensions ~/.julia/packages/RandomExtensions/qAD6J/src/containers.jl:106
```
will make the pass-through methods
```
rand(T::MyAbstractType, v...) = rand(GLOBAL_RNG, T, v...)
```
ambiguous for certain input types (note that I cannot pin down the type of `v` directly, since `T` is abstract and there are many possible combinations).

They are usually fine in practice, but it just looks bad. There are so many, that ignoring them might hide real ambiguities.

首先使用 Aqua.jl 重现歧义报告，并检查 src/containers.jl 中显示的方法，尤其是第 53 行和第 106 行附近的定义。跟踪它们如何与 pass-through 方法 rand(T::MyAbstractType, v...) 交互；当相关歧义已得到理解，并且项目已确定处理或验证这些歧义的方式时，即可视为完成。

由索引模型根据 Issue 内容生成。