Async/Awaited all db methods

This is a rather large PR which updates the async branch to have all the
database methods as an async fn.

Some iter/map logic needed to be changed to a stream::iter().then(), but
besides that most changes were just adding async/await where needed.

rustfmt.toml

@@ -1,7 +1,7 @@
-version = "Two"
-edition = "2018"
+#version = "One"
+edition = "2021"
 max_width = 120
 newline_style = "Unix"
 use_small_heuristics = "Off"
-struct_lit_single_line = false
-overflow_delimited_expr = true
+#struct_lit_single_line = false
+#overflow_delimited_expr = true