Add getting list of hosts with ports from --host param

[df530]

Changelog category (leave one):

• New Feature

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
The param --host can receive list of <host>[:<port>]. In the future client will use it to choose host for connection. If port isn't assigned, it's got from --port param. Choise of host will be depend on availability and workload of hosts.

Detailed description / Documentation draft:
...

By adding documentation, you'll allow users to try your new feature immediately, not when someone else will have time to document it later. Documentation is necessary for all features that affect user experience in any way. You can add brief documentation draft above, or add documentation right into your patch as Markdown files in docs folder.

If you are doing this for the first time, it's recommended to read the lightweight Contributing to ClickHouse Documentation guide first.

Information about CI checks: https://clickhouse.tech/docs/en/development/continuous-integration/

[PolyProgrammist]

Use #12