vapi: add python scripts to vpp-dev package

As requested in https://lists.fd.io/g/vpp-api-dev/message/18
three vapi scrips are packaged, destination to share/vpp/.

Also:
+ Add "vapi" as a separate component to maintainers file.
+ Add also vppapigen/generate_json.py to share/vpp/.
+ Improve CMakeLists.txt indentation.

Type: feature

Change-Id: Ia06715621aa344e8ee759410b293509a54f81fdd
Signed-off-by: Vratko Polak <vrpolak@cisco.com>
diff --git a/src/tools/vppapigen/CMakeLists.txt b/src/tools/vppapigen/CMakeLists.txt
index ce25cb0..9fb0081 100644
--- a/src/tools/vppapigen/CMakeLists.txt
+++ b/src/tools/vppapigen/CMakeLists.txt
@@ -21,4 +21,13 @@
   COMPONENT vpp-dev
 )
 
-install(FILES vppapigen_c.py vppapigen_json.py DESTINATION share/vpp COMPONENT vpp-dev)
+install(
+  FILES
+    vppapigen_c.py
+    vppapigen_json.py
+    generate_json.py
+  DESTINATION
+    share/vpp
+  COMPONENT
+    vpp-dev
+)