cobs_encode() name clashing at runtime

[Richard-Stump]

A user on VTOW discovered that implementing his own cobs_encode function caused his program to crash at runtime, with the stack trace showing only the address 0x3805820.

I believe the issue is that our implementation of cobs_encode in src/common/cobs.c is a public symbol, so when the hot and cold packages link at runtime, the links their cobs_encode calls to our implementation. The main thing is that the symbols for our implementation should be stripped.

This should be investigated further to see if cobs_encode_measure also causes this issue, and if any other functions in the kernel cause this issue.