IVGCVSW-5619 Enable OptimizerOptions for the python external delegate

 * Add reduce-fp32-to-fp16, reduce-fp32-to-bf16, debug-data, memory-import
options to external delegate
 * Simplify DelegateOptions
 * Add test mock models
 * Unit tests
 * Configure lfs to manage tflite files

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I1e4db468862ba03d4cb031347bc307cf940b3cb1
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..7d63010
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+*.tflite filter=lfs diff=lfs merge=lfs -text