[firmware] Add better versioning scheme

[kbhomes]

Goals for a better versioning scheme:

• Support a more human-readable identifier (like SemVer)
  • Currently using a uint16_t as a flat number for the version number
  • Consider changing to something like uint64_t, with a byte pattern such as:
  • Major: 1 byte
  • Minor: 2 bytes
  • Patch: 4 bytes
  • Metadata: 1 byte (for example, dev for local builds, latest for automatic builds)
• Automatically bump patch version with every commit (?)
• Automatically create versioned and latest GitHub releases on commits
  • Use ps2link's GitHub Actions workflow as an example
  • Briefly:
  • For all commits, create a latest release that is tagged as prerelease
  • For commits which are tagged

Not sure what the best strategy is for making sure the versions in the application and in Git stay in sync. Maybe keep major/minor in code, and patch and metadata passed in from the environment. Patch number might be "number of commits since last tag", and tags will always be "\.\.0". This could be problematic if the commit history isn't linear -- need to think about that.