[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>

swift/Sources/FlatBuffers/Table.swift

@@ -137,7 +137,6 @@ public struct Table {
     if offset == 0 {
       return 0
     }
-
     return vector(count: offset)
   }