add kiss radio env to most of the variants

variants/thinknode_m5/platformio.ini

@@ -227,3 +227,8 @@ lib_deps =
   ${ThinkNode_M5.lib_deps}
   densaugeo/base64 @ ~1.4.0
   end2endzone/NonBlockingRTTTL@^1.3.0
+
+[env:ThinkNode_M5_kiss_modem]
+extends = ThinkNode_M5
+build_src_filter = ${ThinkNode_M5.build_src_filter}
+  +<../examples/kiss_modem/>