control connection creation error handling

[rukai]

Previously shotover would give up if the node it tried to use for its control connection was down.
Now it sequentially attempts all other nodes it knows about until it either runs out of nodes reporting an error or makes a successful connection.

An error is returned if no successful connections could be made:

A warning is emitted if any failures occur but a successful connection could still be made in the end.

[github-actions]

3 benchmark regressed. 1 benchmark improved. Please check the benchmark workflow logs for full details: https://github.com/shotover/shotover-proxy/actions/runs/3358416174

cassandra/protect_local_execute_unencrypted
                        time:   [786.49 us 841.32 us 904.67 us]
                        thrpt:  [1.1054 Kelem/s 1.1886 Kelem/s 1.2715 Kelem/s]
                 change:
                        time:   [+22.714% +31.995% +41.478%] (p = 0.00 < 0.05)
                        thrpt:  [-29.318% -24.240% -18.509%]
                        Performance has regressed.
--
�[2m2022-10-31T04:11:16.124584Z�[0m �[33m WARN�[0m �[2mshotover_proxy::transforms::distributed::consistent_scatter�[0m�[2m:�[0m Using this transform is considered unstable - Does not work with REDIS pipelines
redis/active_set        time:   [286.13 us 304.30 us 327.01 us]
                        thrpt:  [3.0580 Kelem/s 3.2863 Kelem/s 3.4949 Kelem/s]
                 change:
                        time:   [+39.477% +47.299% +54.729%] (p = 0.00 < 0.05)
                        thrpt:  [-35.371% -32.111% -28.303%]
                        Performance has regressed.
--
  6 (6.00%) high severe
redis/single_tls        time:   [213.24 us 227.67 us 244.60 us]
                        thrpt:  [4.0884 Kelem/s 4.3923 Kelem/s 4.6895 Kelem/s]
                 change:
                        time:   [+33.102% +41.517% +50.199%] (p = 0.00 < 0.05)
                        thrpt:  [-33.422% -29.337% -24.870%]
                        Performance has regressed.

cassandra/passthrough_parse_request_select
                        time:   [883.62 us 915.60 us 952.82 us]
                        thrpt:  [1.0495 Kelem/s 1.0922 Kelem/s 1.1317 Kelem/s]
                 change:
                        time:   [-46.387% -41.507% -35.716%] (p = 0.00 < 0.05)
                        thrpt:  [+55.560% +70.961% +86.522%]
                        Performance has improved.