[framework] Review basic functions for efficiency and add new natives as needed

[wrwg]

move-stdlib has some unnecessary inefficiencies in the basic libraries for vectors and strings. For instance:

public fun append<Element>(lhs: &mut vector<Element>, other: vector<Element>) {
        reverse(&mut other);
        reverse_append(lhs, other);
 }
 
 public fun reverse_append<Element>(lhs: &mut vector<Element>, other: vector<Element>) {
        let len = length(&other);
        while (len > 0) {
            push_back(lhs, pop_back(&mut other));
            len = len - 1;
        };
        destroy_empty(other);
 }

The reverse operation is unnecessary if this would be implemented on native level.

There might be other cases. Moreover, in some cases missing functions (like replace on string) need native implementations to be really efficient, and should therefore be added.