*: replace interface{} with any keyword

Everywhere including examples, external interop APIs, bindings generators
code and in other valuable places. A couple of `interface{}` usages are
intentionally left in the CHANGELOG.md, documentation and tests.

examples/iterator/iterator.go

@@ -7,7 +7,7 @@ import (
 )
 
 // _deploy primes contract's storage with some data to be used later.
-func _deploy(_ interface{}, _ bool) {
+func _deploy(_ any, _ bool) {
 	ctx := storage.GetContext() // RW context.
 	storage.Put(ctx, "foo1", "1")
 	storage.Put(ctx, "foo2", "2")