Add version to build info, share with syrctl

[Mierdin]

This PR adds a "version" field to the buildinfo struct generated at compile time.

This will get set to "dev-" in most cases during development, but if the current SHA matches a git tag, it will be set to that tag. This will allow us to predictably place the correct version into both syrctl and syringed without having to manually update it from version to version.

[codecov]

Codecov Report

Merging #90 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #90   +/-   ##
=======================================
  Coverage   23.48%   23.48%           
=======================================
  Files          18       18           
  Lines        1916     1916           
=======================================
  Hits          450      450           
  Misses       1412     1412           
  Partials       54       54

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 23841e7...d9eece0. Read the comment docs.