doc: add new section 'Developing with Zephyr'

Move all introductionary docs into one new section.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/doc/getting_started/img/ReelBoard-Blinky.png b/doc/develop/getting_started/img/ReelBoard-Blinky.png
similarity index 100%
rename from doc/getting_started/img/ReelBoard-Blinky.png
rename to doc/develop/getting_started/img/ReelBoard-Blinky.png
Binary files differ
diff --git a/doc/getting_started/index.rst b/doc/develop/getting_started/index.rst
similarity index 100%
rename from doc/getting_started/index.rst
rename to doc/develop/getting_started/index.rst
diff --git a/doc/getting_started/installation_linux.rst b/doc/develop/getting_started/installation_linux.rst
similarity index 100%
rename from doc/getting_started/installation_linux.rst
rename to doc/develop/getting_started/installation_linux.rst
diff --git a/doc/getting_started/installation_mac.rst b/doc/develop/getting_started/installation_mac.rst
similarity index 100%
rename from doc/getting_started/installation_mac.rst
rename to doc/develop/getting_started/installation_mac.rst
diff --git a/doc/getting_started/installation_win.rst b/doc/develop/getting_started/installation_win.rst
similarity index 100%
rename from doc/getting_started/installation_win.rst
rename to doc/develop/getting_started/installation_win.rst
diff --git a/doc/getting_started/toolchain_3rd_party_x_compilers.rst b/doc/develop/getting_started/toolchain_3rd_party_x_compilers.rst
similarity index 100%
rename from doc/getting_started/toolchain_3rd_party_x_compilers.rst
rename to doc/develop/getting_started/toolchain_3rd_party_x_compilers.rst
diff --git a/doc/getting_started/toolchain_custom_cmake.rst b/doc/develop/getting_started/toolchain_custom_cmake.rst
similarity index 100%
rename from doc/getting_started/toolchain_custom_cmake.rst
rename to doc/develop/getting_started/toolchain_custom_cmake.rst
diff --git a/doc/getting_started/toolchain_host.rst b/doc/develop/getting_started/toolchain_host.rst
similarity index 100%
rename from doc/getting_started/toolchain_host.rst
rename to doc/develop/getting_started/toolchain_host.rst
diff --git a/doc/getting_started/toolchain_other_x_compilers.rst b/doc/develop/getting_started/toolchain_other_x_compilers.rst
similarity index 100%
rename from doc/getting_started/toolchain_other_x_compilers.rst
rename to doc/develop/getting_started/toolchain_other_x_compilers.rst
diff --git a/doc/index-tex.rst b/doc/index-tex.rst
index 4a9f6c3..dea5549 100644
--- a/doc/index-tex.rst
+++ b/doc/index-tex.rst
@@ -14,7 +14,7 @@
    :caption: Contents
 
    introduction/index.rst
-   getting_started/index.rst
+   develop/index.rst
    contribute/index.rst
    build/index.rst
    kernel/index.rst
diff --git a/doc/index.rst b/doc/index.rst
index f1d8bf2..72fd1c1 100644
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -102,7 +102,7 @@
    :caption: Contents
 
    introduction/index.rst
-   getting_started/index.rst
+   develop/index.rst
    contribute/index.rst
    development_process/index.rst
    application/index.rst