pw_blob_store: Add write support

Add BlobStore write implementation
Add initial BlobStore tests.
Add missing CMake build files in dependency modules to unbreak CMake
build.

Still missing:
Cleanup validation checking
KVS handling/usage
Some better testing

Change-Id: Ie6b711598a917d7553b5a682d8ef36cdcc137303
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/16040
Commit-Queue: David Rogers <davidrogers@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
diff --git a/pw_stream/CMakeLists.txt b/pw_stream/CMakeLists.txt
new file mode 100644
index 0000000..1d17437
--- /dev/null
+++ b/pw_stream/CMakeLists.txt
@@ -0,0 +1,26 @@
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+pw_auto_add_simple_module(pw_stream
+  PUBLIC_DEPS
+    pw_bytes
+    pw_containers
+    pw_log
+    pw_result
+    pw_span
+    pw_status
+  PRIVATE_DEPS
+    pw_assert
+    pw_string
+)