Improve version strings

[Mirko-von-Leipzig]

Improve the output of our miden-xxx --version output to account for non-release builds, such as we might deploy on devnet instances.

Use git describe --tags --dirty which will give us the format

<version-tag>-<commit-count>-<commit SHA>-dirty

where everything but <version-tag> is only present if applicable.

This will also help us debug operator node's as we can now know if they're on a non-release build.

[bobbinth]

Closed by #495.