refactor: reintroduce single device simulator as an uplink built-in

[de-sh]

Closes #

Currently built-in simulator works with the principle of multi-device simulation, which doesn't work for certain parts like the TLS reliant downloader, thus it was necessary to create a simulator.sh that runs a utility along with uplink to simulate data. Since then we have progressed a lot and the complexity of multi-device simulation support has become a thorn in the code's readability and with this change removing the same is the goal.

Changes

• Copy code from tools/simulator into collector/simulator and refactor it to work within uplink as a built-in
• Remove all code in uplink that is there only to supports multi-device simulation
• Update simulator.sh to use built-in-sim

Why?

This will decrease the complexity of simulator.sh by quite a bit and since we have fewer processes running, could also impact performance.

Trials Performed

Run simulator.sh with appropriate env vars, contents of devices/uplink_<device_id>.log