Support multiple nodes

[cortadocodes]

Summary

Upgrade data-gateway to handle data from multiple nodes instead of one. This pull request pulls together the changes from the following pull requests - view each one for their individual release notes:

• Update Configuration class to support multiple nodes #70
• Convert packet reader to allow multiple nodes #71
• Fix bugs, simplify/fix dependencies, and improve deployment process #60
• Improve Raspberry Pi installation process #72
• Manage Raspberry Pi deployment via Balena #81

Breaking changes and changes separate from these PRs are listed below.

Contents (#69)

IMPORTANT: There are 2 breaking changes.

New features

• 💥 BREAKING CHANGE: Update configuration for multiple nodes (see #64)

Operations

• Prevent serialisation error in window handler debugging statement
• Make workflows apply correct memory
• Remove old cloudbuild.yaml file

Refactoring

• 💥 BREAKING CHANGE: Remove incorrectly parameterised default sensor name

---

Upgrade instructions

💥 Remove incorrectly parameterised default sensor name

MICROPHONE_SENSOR_NAME is no longer exported

This was removed because it was a misnomer (actually should have been called DEFAULT_MICROPHONE_SENSOR_NAME).

It's very unlikely this will cause any onward breaking changes, but if using that variable externally, the user should instead access data_gateway.configuration.DEFAULT_SENSOR_NAMES[0] which is the same thing.

💥 Update configuration for multiple nodes per #64

Configuration values nested and separated by concerns.

• Users should consult docs for the new configuration format. Older configuration.json files will no longer work so need to be updated.

• Periods are now calculated rather than being configurable, to eliminate duplication. Users should
  configure the relevant frequency parameters for the sensors.

• The session_data key was converted to session

• The ambiguous hardware_version key was removed and replaced with gateway.receiver_firmware_versionandnodes[node_id].node_firmware_version`

• The packet_key is no longer present, instead use Configuration().get_packet_key(node_id)