Implement random server port assignment when the 'local' part is not …

…specified (either on CLI or API request)

New CLI option --exclude-ports added to allow server administrators to specify ports forbidden to use

Merge pull request #15 from cloudradar-monitoring/logging-to-file

Allow logging to a file and specifying log verbosity (error, info, debug)

Rework CLI args naming

- -l and -p options were merged into --addr (-a) option.
- help updated with IPv6 addresses usage
- typos fixed in README

Merge pull request #11 from cloudradar-monitoring/DEV-1591

better identification of clients

refactor to reduce cyclomatic complexity

Add option to serve static files when running API server

Merge pull request #3 from cloudradar-monitoring/circleci-automation

Add CircleCI config and it's dependencies

Add CircleCI config and it's dependencies

Improve server and client usage in various scenarios

- Update env variables naming
- Improve --help output and add examples
- Fix handling --authfile restrictions
- Do not exit client on authentication errors

Fix goreleaser archives creation