Parse parentheses

SearchQL should be able to parse parentheses.

Given the query:

```
foo AND (bar OR qux)
```

SearchQL should parse the query as:

```elixir
[data: "foo", or: {
   [data: "bar"], [data: "qux"]}]
```

Rather than:

```elixir
[or: {
  [data: "foo", data: "(bar"]},
  [data: "qux)"]}]
```