feat(rollup): init telemetry

[merklefruit]

Added the ability to start tracing to stdout with the following options:

• tracing target: provided by default with RUST_LOG directives. Falls back to hera=info if not provided.
• whether to show the target in stdout: RUST_LOG_TARGET (don't show it only when set to 0)
• whether to use ANSI formatting and colors: RUST_LOG_STYLE (don't use it only if set to never)

Also initialized a Prometheus subscriber on the provided port.
Tested on the Hera binary.

closes #33

[refcell]

Nice, like the use of RUST_LOG_TARGET