Add west.yml

Adding west.yml resolves the first issue when building with west.

`west build -p always -b nrf52840dk_nrf52840
mcuboot/samples/zephyr_external_config` now fails with:

  error: MCUBOOT (defined at Kconfig.zephyr:682) is assigned in a configuration file, but is not
  directly user-configurable (has no prompt). It gets its value indirectly from other symbols. See
  http://docs.zephyrproject.org/latest/kconfig.html#CONFIG_MCUBOOT and/or look up MCUBOOT in the
  menuconfig/guiconfig interface. The Application Development Primer, Setting Configuration Values,
  and Kconfig - Tips and Best Practices sections of the manual might be helpful too.

  CMake Error at /home/zephyr/mcuboot_dev/zephyr/cmake/modules/kconfig.cmake:326 (message):
    command failed with return code: 1
  Call Stack (most recent call first):
    /home/zephyr/mcuboot_dev/zephyr/cmake/modules/zephyr_default.cmake:108 (include)
    /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
    /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
    CMakeLists.txt:6 (find_package)

Signed-off-by: Gregory SHUE <[email protected]>

Author: legrand-gregshue

west.yml

@@ -0,0 +1,32 @@
+# Copyright (c) 2022 Legrand North America, LLC.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# The west manifest file for Zephyr ecosystem development.
+#
+# Usage:
+# west init -m https://github.com/mcu-tools/mcuboot
+# west update
+
+manifest:
+  version: "0.12"
+
+  remotes:
+    - name: zephyrproject
+      url-base: https://github.com/zephyrproject-rtos
+    - name: mcu-tools
+      url-base: https://github.com/mcu-tools
+
+  defaults:
+    remote: mcu-tools
+
+  projects:
+    - name: zephyr
+      revision: main
+      remote: zephyrproject
+      import:
+        name-blocklist:
+          - mcuboot
+
+  self:
+    path: mcuboot