chore: add log levels

[rackstar]

Description

• add @nexusmutual/utils as dependency (which contains log-level lib)
• differentiate logs to different console methods to utilise log levels

cover-router logging:

• for each end-point we log the request params as well as the API response (except for /capacity as its too verbose)
• I went through all the consoles and aside from logging the responses the only objects we log that I can see is poolsData when we encounter an error (these is now under debug log)
• as far as I can tell, all the other consoles only log non-objects aside from these

Testing

manually tested locally

Checklist

• Performed a self-review of my own code
• Made corresponding changes to the documentation

[rackstar]

marking a draft until @nexusmutual/utils 0.0.1 has been publish

EDIT: marked as ready