Optional call chain can be simplified

Reports Optional call chains that can be simplified. Here are several examples of possible simplifications:

• optional.map(x -> true).orElse(false) → optional.isPresent()

• optional.map(x -> Optional.of(x.trim())).orElseGet(Optional::empty) → optional.map(String::trim)

• optional.map(x -> (String)x).orElse(null) → (String) optional.orElse(null)

• Optional.ofNullable(optional.orElse(null)) → optional

• val = optional.orElse(null); val != null ? val : defaultExpr → optional.orElse(defaultExpr)

• val = optional.orElse(null); if(val != null) expr(val) → optional.ifPresent(val -> expr(val))

New in 2017.2