`sort`/`sort-by` does not properly work on maps

[ikappaki]

sort and sort-by on a map return the map keys rather than sorted sequences.

to reproduce

1. Open up a REPL and try to sort a map with some entries

basilisp.user=> (sort {:2 1 :1 3 :3 2})
;; => (:1 :2 :3)

2. The values returned are the sorted keys rather than a two pair sequences representing the key value pairs.

The same on Clojure returns

user> (sort {:2 1 :1 3 :3 2})
;; => ([:1 3] [:2 1] [:3 2])

sort-by throws an error instead:

basilisp.user=> (sort-by first {:2 1 :1 3 :3 2})
...
  File "C:\src\basilisp\src\basilisp\lang\seq.py", line 255, in sequence
    i = iter(s)
        ^^^^^^^
TypeError: 'Keyword' object is not iterable

while on clojure

user>  (sort-by first {:2 1 :1 3 :3 2})
;; => ([:1 3] [:2 1] [:3 2])

Exploratory PR to follow.