doc(import_cc): Add initial documentation for attributes

Change-Id: Ia929fdafc8d0e42ea53ffe99be869ef8e0877a3e

Author: BrandonThomasJonesARM

docs/module_types/bob_import_cc.md

@@ -0,0 +1,22 @@
+# Module: bob_import_cc
+
+> ⚠ Warning, this target is experimental & the attributes/interface are likely to keep changing. ⚠
+
+```bp
+bob_import_cc {
+    name, src, includes, defines, target, linkopts
+}
+```
+
+This target exists to include externally built libraries into the linux build graph. This is to better enable a future transition to bazel.
+
+## Properties
+
+|                                                |                                                                                                                                                   |
+| ---------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- | --- |
+| [`name`](properties/common_properties.md#name) | String; required                                                                                                                                  |
+| `src`                                          | Optional, path of the built library, leave empty for a header only library.                                                                       |
+| `includes`                                     | List of include dirs needed to link against the external library.                                                                                 |
+| `target`                                       | one of either `host` or `target`. Whether the library is built for host or target.                                                                |
+| `defines`                                      | List of strings; default is `[]`<br>Defines that are included in the local module, and all modules that depend upon it. (Including transitively.) |     |
+| [`linkopts`](properties/linkopts.md)           | List of strings; default is `[]`<br>List of additional flags to the linker command.                                                               |