agnostic auto-loader, retiring diad's loader (#59)

* updating stadard tomo to auto, removing diads loader

* corrections to directives

Author: dkazanc

httomo_backends/pipelines_full/gpu_diad_FBP_directive.yaml

@@ -1,4 +1,4 @@
-- method: standard_tomo_diad
+- method: standard_tomo
   module_path: httomo.data.hdf.loaders
 - method: find_center_vo
   module_path: httomolibgpu.recon.rotation

httomo_backends/pipelines_full/gpu_diad_FBP_noimagesaving_directive.yaml

@@ -1,4 +1,4 @@
-- method: standard_tomo_diad
+- method: standard_tomo
   module_path: httomo.data.hdf.loaders
 - method: find_center_vo
   module_path: httomolibgpu.recon.rotation

httomo_backends/yaml_templates/httomo/httomo.data.hdf.loaders/standard_tomo.yaml

@@ -1,10 +1,9 @@
 - method: standard_tomo
   module_path: httomo.data.hdf.loaders
   parameters:
-    data_path: /entry1/tomo_entry/data/data
-    image_key_path: /entry1/tomo_entry/instrument/detector/image_key
-    rotation_angles:
-      data_path: /entry1/tomo_entry/data/rotation_angle
+    data_path: auto
+    image_key_path: auto
+    rotation_angles: auto
     preview:
       detector_x:   # horizontal data previewing/cropping.
         # when null, the full data dimension is used, i.e., no previewing