cli: use cargo package version environment data in cli options struct

[q9f]

Summary of changes
Changes introduced in this pull request:

• version mismatch between CLI and Cargo.toml fixed
• CLI uses CARGO_PKG_* environment variables to reduce the duplicated text
• create a build.rs script that determines a meaningful version string at build time
• defines a RELEASE_TRACK which can be used in future
• use --features release for tag releases

Other information and links

~/.opt/chainsafe/forest q9f/cli/release*
❯ cargo build --bin forest
    Finished dev [unoptimized + debuginfo] target(s) in 0.23s

~/.opt/chainsafe/forest q9f/cli/release*
❯ target/debug/forest --version
forest v0.1.0/unstable/fb019318

~/.opt/chainsafe/forest q9f/cli/release*
❯ cargo build --release --bin forest --features release
    Finished release [optimized] target(s) in 0.25s

~/.opt/chainsafe/forest q9f/cli/release*
❯ target/release/forest --version
forest v0.1.0/alpha/fb019318

[ec2]

lgtm