Add python backend support

- Modify dockerfile to include bitsandbytes, transformers and latest version of pytorch
- Minor modifications in utils/codegen.py so that same client works with FT and Py-backend
- Minor modifications in launch.sh (no need to name models by GPU)
- Add installation script for adding a new python model (with super simple config_template)
- Modify setup.sh so that it aworks with both FT and Python backend models

Signed-off-by: Parth Thakkar <thakkarparth007@gmail.com>

python_backend/config_template.pbtxt

@@ -0,0 +1,180 @@
+name: "py-model"
+backend: "python"
+max_batch_size: 4
+input [
+  {
+    name: "input_ids"
+    data_type: TYPE_INT32
+    dims: [ -1 ]
+  },
+  {
+    # UNUSED
+    name: "start_id"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "end_id"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    name: "input_lengths"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+  },
+  {
+    name: "request_output_len"
+    data_type: TYPE_INT32
+    dims: [ -1 ]
+  },
+  {
+    name: "runtime_top_k"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    name: "runtime_top_p"
+    data_type: TYPE_FP32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "beam_search_diversity_rate"
+    data_type: TYPE_FP32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    name: "temperature"
+    data_type: TYPE_FP32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "len_penalty"
+    data_type: TYPE_FP32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "repetition_penalty"
+    data_type: TYPE_FP32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "random_seed"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "is_return_log_probs"
+    data_type: TYPE_BOOL
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "beam_width"
+    data_type: TYPE_INT32
+    dims: [ 1 ]
+    reshape: { shape: [ ] }
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "bad_words_list"
+    data_type: TYPE_INT32
+    dims: [ 2, -1 ]
+    optional: true
+  },
+  {
+    # UNUSED
+    name: "stop_words_list"
+    data_type: TYPE_INT32
+    dims: [ 2, -1 ]
+    optional: true
+  }
+]
+output [
+  {
+    name: "output_ids"
+    data_type: TYPE_INT32
+    dims: [ -1, -1 ]
+  },
+  {
+    name: "sequence_length"
+    data_type: TYPE_INT32
+    dims: [ -1 ]
+  } #,
+# Following is currently unsupported, but should be supported in the future
+#  {
+#    name: "cum_log_probs"
+#    data_type: TYPE_FP32
+#    dims: [ -1 ]
+#  },
+#  {
+#    name: "output_log_probs"
+#    data_type: TYPE_FP32
+#    dims: [ -1, -1 ]
+#  }
+]
+# unsure what this is for
+instance_group [
+  {
+    count: 1
+    kind: KIND_CPU
+  }
+]
+parameters {
+  key: "use_half"
+  value: {
+    string_value: "1"
+  }
+}
+parameters {
+  key: "model_name"
+  value: {
+    string_value: "${model_name}" # e.g. "codegen-350M-multi"
+  }
+}
+parameters {
+  key: "org_name"
+  value: {
+    string_value: "${org_name}" # e.g. "Salesforce"
+  }
+}
+parameters {
+  key: "use_int8",
+  value: {
+    string_value: "${use_int8}" # e.g. "0" or "1"
+  }
+}
+parameters {
+  key: "use_auto_device_map",
+  value: {
+    string_value: "${use_auto_device_map}" # e.g. "0" or "1"
+  }
+}