Handle hub availability better

[artemijspavlovs]

the requests sent to the hub should first check whether the endpoint is healthy and wait with a certain timeout if it's not, currently it's returning an error which doesn't provide any information about the root cause of the error

  ERROR   failed to check if sequencer is already registered: command execution failed: exit status 1, stderr: Error: error in json rpc client, with http response metadata: (Status: 502 Bad Gateway, Protocol HTTP/1.1). error unmarshalling: invalid character '<' looking for beginning of value
          Usage:
            dymd query sequencer show-sequencers-by-rollapp [rollapp-id] [flags]

          Flags:
                --count-total        count total number of records in show-sequencers-by-rollapp [rollapp-id] to query for
                --grpc-addr string   the gRPC endpoint to use for this chain
                --grpc-insecure      allow gRPC over insecure channels, if not TLS the server must use TLS
                --height int         Use a specific height to query state at (this can error if the node is pruning state)
            -h, --help               help for show-sequencers-by-rollapp
                --limit uint         pagination limit of show-sequencers-by-rollapp [rollapp-id] to query for (default 100)
                --node string        <host>:<port> to Tendermint RPC interface for this chain (default "tcp://localhost:26657")
                --offset uint        pagination offset of show-sequencers-by-rollapp [rollapp-id] to query for
            -o, --output string      Output format (text|json) (default "text")
                --page uint          pagination page of show-sequencers-by-rollapp [rollapp-id] to query for. This sets offset to a multiple of limit (default 1)
                --page-key string    pagination page-key of show-sequencers-by-rollapp [rollapp-id] to query for
                --reverse            results are sorted in descending order

          Global Flags:
                --chain-id string     The network chain ID
                --home string         directory for config and data (default "/home/ubuntu/.dymension")
                --log_format string   The logging format (json|plain) (default "plain")
                --log_level string    The logging level (trace|debug|info|warn|error|fatal|panic) (default "info")
                --log_no_color        Disable colored logs
                --trace               print out full stack trace on errors