refactor: create fixtures module

Prepare for adding a second radically different fixture by creating a
module to hold the different fixtures. When I only had one fixture it
was ok to have the module be a single file.

src/exec/mod.rs

@@ -1,5 +1,4 @@
 use crate::elm;
-use crate::fixture;
 use crate::reporting::{CompilerError, InterpreterError, Problem, SetupError, TypeError};
 use crate::PortableHash;
 use deno_core::futures::StreamExt;
@@ -19,6 +18,8 @@ use std::time::Instant;
 use tokio;
 use tracing::{info_span, Instrument};
 
+mod fixtures;
+
 #[derive(Serialize)]
 #[serde(tag = "$")]
 pub(crate) enum ElmResult<T, E> {
@@ -104,7 +105,7 @@ pub(crate) fn exec(
     // step 7 create an Elm fixture file to run our function
     let span = info_span!("create Elm fixture files");
     let timing_guard = span.enter();
-    let (gen_module_name, source) = fixture::generate(
+    let (gen_module_name, source) = fixtures::scripting::generate(
         source_checksum,
         entrypoint.0.module.clone(),
         entrypoint.1.clone(),
@@ -194,7 +195,7 @@ pub(crate) fn exec(
             final_script = final_script
                 .replace(
                     "var $author$project$Astrid$Query$execute = function (query) {\n\treturn $author$project$Astrid$Query$dummyExecute;\n};",
-                    include_str!("../fixture/query.js"),
+                    include_str!("fixtures/sql-client-integration.js"),
                 )
                 .replace(
                     "var $author$project$Astrid$Query$fetch = F3(\n\tfunction (sql, parameters, decoder) {\n\t\treturn $author$project$Astrid$Query$Dummy;\n\t});",