Python: gpu module: add new submodules and types

This commit extends the gpu python API with:
```
gpu.types.Buffer         #"__init__", "to_list"
gpu.types.GPUTexture     #"__init__", "clear", "read", "format"
gpu.types.GPUFrameBuffer #"__init__", "bind", "clear", "is_bound", "viewport", ("__enter__",  "__exit__" with "GPUFrameBufferStackContext")
gpu.types.GPUUniformBuf  #"__init__", "update"
gpu.state                #"blend_set",  "blend_get",  "depth_test_set",  "depth_test_get",  "depth_mask_set",  "depth_mask_get",  "viewport_set",  "viewport_get",  "line_width_set",  "line_width_get",  "point_size_set",  "color_mask_set",  "face_culling_set", "front_facing_set",  "program_point_size_set"
```

Add these methods to existing objects:
```
gpu.types.GPUShader  #"uniform_sample", "uniform_buffer"
```

Maniphest Tasks: T80481

Differential Revision: https://developer.blender.org/D8826

source/blender/python/gpu/gpu_py.c

@@ -0,0 +1,45 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup bpygpu
+ *
+ * - Use ``bpygpu_`` for local API.
+ * - Use ``BPyGPU`` for public API.
+ */
+
+#include <Python.h>
+
+#include "GPU_texture.h"
+
+#include "../generic/py_capi_utils.h"
+
+#include "gpu_py.h" /* own include */
+
+/* -------------------------------------------------------------------- */
+/** \name GPU Module
+ * \{ */
+
+struct PyC_StringEnumItems bpygpu_dataformat_items[] = {
+    {GPU_DATA_FLOAT, "FLOAT"},
+    {GPU_DATA_INT, "INT"},
+    {GPU_DATA_UNSIGNED_INT, "UINT"},
+    {GPU_DATA_UNSIGNED_BYTE, "UBYTE"},
+    {GPU_DATA_UNSIGNED_INT_24_8, "UINT_24_8"},
+    {GPU_DATA_10_11_11_REV, "10_11_11_REV"},
+    {0, NULL},
+};
+/** \} */