Remove old sensu service and rename sensu0_13

Both teams using sensu are now on a version which works with the
sensu0_13 service, so we can rename this
These functions should be pulled out instead of being inlined so that they're easier to read.

Clojure has a few different ways of using the same function name depending on your needs. In this case, you're after a multi-arity function which can be defined using the `defn` macro. Here's a simple example of a multi-arity function:

```clojure
(defn string->integer 
  ([s] (string->integer s 10))
  ([s base] (Integer/parseInt s base)))
```

The equivalent for your implementation of `matches-filter-params?` would be something like:

```clojure
(defn matches-filter-params?
  ([filter-params alert]
     (every? (partial matches-filter-params? filter-params alert) (keys filter-params)))
  ([filter-params alert key]
     (let [filter-param (filter-params key)
           alert        (alert key)]
       (if (map? filter-param)
         (matches-filter-params? filter-param alert)
         (re-matches (re-pattern filter-param) (str alert))))))
```

In the above case, I've consolidated the `matches-filter-params?` and `matches-filter-param?` functions. This means that the `filter-alerts` function would look something like this:

```clojure
(defn filter-alerts [filter-params alerts]
  (filter #(matches-filter-params? filter-params %) alerts))
```

Worth saying that none of the above blocked this PR going through. Just wanted to make you aware of some ways of reducing code and making things easier to understand.