[Swift] Inline arrays (#8755)

Implements InlineArrays which allow us to use Flatbuffers arrays within
Structs natively, and also implements FlatbufferVectors as a secondary API
when using mutable Structs

Fixes mutations within fixed sizes arrays

Adds tests and remove inout and mutating from generated objects in favor of borrowing

---------

Co-authored-by: Wouter van Oortmerssen <aardappel@gmail.com>

scripts/generate_code.py

@@ -451,6 +451,13 @@ flatc(
     include="include_test",
     prefix=swift_prefix,
 )
+
+flatc(
+    SWIFT_OPTS + BASE_OPTS,
+    schema="arrays_test.fbs",
+    prefix=swift_prefix,
+)
+
 flatc(
     SWIFT_OPTS + BASE_OPTS,
     schema="union_vector/union_vector.fbs",