add kiss radio env to most of the variants

variants/keepteen_lt1/platformio.ini

@@ -99,4 +99,9 @@ build_src_filter = ${KeepteenLT1.build_src_filter}
   +<../examples/companion_radio/ui-new/*.cpp>
 lib_deps = ${KeepteenLT1.lib_deps}
   adafruit/RTClib @ ^2.1.3
-  densaugeo/base64 @ ~1.4.0
+  densaugeo/base64 @ ~1.4.0
+
+[env:KeepteenLT1_kiss_modem]
+extends = KeepteenLT1
+build_src_filter = ${KeepteenLT1.build_src_filter}
+  +<../examples/kiss_modem/>