Enable bitbang I2C on IOT01 board

Move things around a bit - consolidate platform manifests into the root manifest, move sources under src/$platform directories

CL: Enable bitbang I2C on IOT01 board

PUBLISHED_FROM=8ac2b9711ce00bc595b7281dff332e66fefd6692

mos.yml

@@ -36,6 +36,7 @@ conds:
   - when: build_vars.BOARD == "B-L475E-IOT01A"
     apply:
       libs:
+        - origin: https://github.com/mongoose-os-libs/rpc-service-i2c
         - origin: https://github.com/mongoose-os-libs/rpc-service-wifi
 
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