Add missing, basic bool operations

[benikm91]

Add missing basic Boolean operations. However, we must decide how to do this. I propose that there must be exactly one way to do it, so we must pick one of the following:

t and t2 // Notation proposed in this PR
t.and(t2) // Alternative A
t && t2 // Alternative B
t & t2 // Alternative C
t + t2 // Alternative D

Why not Alternative A: I think and is an operator, so infix seems correct to me.
Why not Alternative B: && means short-circuiting, which is wrong in tensorland.
Why not Alternative C: & valid alternative for me. I like "and" just better
Why not Alternative D: + is not that clear; e.g., true + true could also be false to me (finite space).

Broadcasting would look like this; note and! is impossible due to Scala syntax constraints:

t and_! t2 // Notation proposed in this PR
t &! t2 // Alternative C

Here is an overview of the PR and Alternative C for all boolean operations (broadcasted):

 // Notation proposed in this PR
t and_! t2
t or_! t2
t xor_! t2

// Alternative C (not supported)
t &! t2 
t |! t2 
t ^! t2 

Note: I see the _! not as a disadvantage, as I envision similar broadcasting for e.g. where in the future:

// current
val maskedScores = where(attentionMask, attentionScores, Tensor.like(attentionScores).fill(Float.NegativeInfinity))
// future
val maskedScores = where_!(attentionMask, attentionScores, Float.NegativeInfinity)

But this will be a separate PR, let's not discuss where here.

[marcelluethi]

I like the syntax for both the logical operations and the broadcasting.
Let's try it.