Go client: Allow configuring the startup timeout

[kaklakariada]

Sometimes startup fails with the following error message, e.g. for this build:

failed to start server. The server did not print a port number. Output: "", error stream: "2023-10-18 09:03:07.649 [INFO   ] Starting exasol test setup using dummy config file\n2023-10-18 09:03:07.807 [INFO   ] Using Exasol test container setup (auto mode with configuration file non-existing-config-file-1697619787800.json missing)\n2023-10-18 09:03:08.207 [INFO   ] Image name substitution will be performed by: DefaultImageNameSubstitutor (composite of 'ConfigurationFileImageNameSubstitutor' and 'PrefixingImageNameSubstitutor')\n2023-10-18 09:03:09.204 [INFO   ] Found Docker environment with local Unix socket (unix:///var/run/docker.sock)\n2023-10-18 09:03:09.257 [INFO   ] Docker host IP address is localhost\n2023-10-18 09:03:09.288 [INFO   ] Connected to docker: \n  Server Version: 24.0.6\n  API Version: 1.43\n  Operating System: Ubuntu 22.04.3 LTS\n  Total Memory: 6921 MB\n2023-10-18 09:03:09.309 [INFO   ] Checking the system...\n2023-10-18 09:03:09.311 [INFO   ] ✔︎ Docker server version should be at least 1.6.0\n2023-10-18 09:03:09.315 [FINE   ] Exposing ports: [8563, 2580, 443, 20002, 22]\n2023-10-18 09:03:09.714 [INFO   ] Pulling docker image: exasol/docker-db:8.23.0. Please be patient; this may take some time but only needs to be done once.\n2023-10-18 09:03:10.525 [INFO   ] Starting to pull image\n2023-10-18 09:03:10.566 [INFO   ] Pulling image layers:  0 pending,  0 downloaded,  0 extracted, (0 bytes/0 bytes)\n2023-10-18 09:03:10.773 [INFO   ] Pulling image layers:  5 pending,  1 downloaded,  0 extracted, (405 bytes/? MB)\n2023-10-18 09:03:11.367 [INFO   ] Pulling image layers:  4 pending,  2 downloaded,  0 extracted, (144 MB/? MB)\n2023-10-18 09:03:11.878 [INFO   ] Pulling image layers:  3 pending,  3 downloaded,  0 extracted, (297 MB/? MB)\n2023-10-18 09:03:11.897 [INFO   ] Pulling image layers:  2 pending,  4 downloaded,  0 extracted, (297 MB/? MB)\n2023-10-18 09:03:11.976 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  0 extracted, (310 MB/? MB)\n2023-10-18 09:03:15.713 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  1 extracted, (558 MB/? MB)\n2023-10-18 09:03:25.452 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  2 extracted, (1 GB/? MB)\n2023-10-18 09:03:28.007 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  3 extracted, (1 GB/? MB)\n2023-10-18 09:03:34.176 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  4 extracted, (1 GB/? MB)\n2023-10-18 09:03:34.210 [INFO   ] Pulling image layers:  1 pending,  5 downloaded,  5 extracted, (1 GB/? MB)\n2023-10-18 09:04:01.196 [INFO   ] Pulling image layers:  0 pending,  6 downloaded,  5 extracted, (3 GB/3 GB)\n2023-10-18 09:06:15.457 [INFO   ] Pulling image layers:  0 pending,  6 downloaded,  6 extracted, (3 GB/3 GB)\n2023-10-18 09:06:15.475 [INFO   ] Pull complete. 6 layers, pulled in 184s (downloaded 3 GB at 20 MB/s)\n2023-10-18 09:06:15.523 [INFO   ] Creating container for image: exasol/docker-db:8.23.0\n2023-10-18 09:06:15.744 [INFO   ] Container exasol/docker-db:8.23.0 is starting: ebb9241ec417c7e409592831633eaa4ecfcace56af3bf4aaf6e23d097aa1a29e\n2023-10-18 09:06:16.431 [FINE   ] No status cache found for container \"ebb9241ec417c7e409592831633eaa4ecfcace56af3bf4aaf6e23d097aa1a29e\". Creating fresh status.\n2023-10-18 09:06:16.432 [FINEST ] Waiting for cluster configuration to become available.\n2023-10-18 09:06:17.305 [FINEST ] Docker container supports docker exec\n"

The timeout of 500s = 8.3min seems to be too short in some situations, especially on slow GitHub runners. That's why we should make the timeout configurable for the Go client.