List workflow executions APIs should not require namespace and filter fields

[mfateev]

Expected Behavior

List workflows should default namespace to "default".

Actual Behavior

Namespace argument is required.

[mfateev]

Also if the earliest time is not set then nothing is returned. But if it is set then the latest is required for some reason:

    ListOpenWorkflowExecutionsRequest request =
        ListOpenWorkflowExecutionsRequest.newBuilder()
            .setNamespace("default")
            .setStartTimeFilter(
                StartTimeFilter.newBuilder()
                    .setEarliestTime(
                        TimeUnit.MILLISECONDS.toNanos(System.currentTimeMillis() - 100000))
                    //                    .setLatestTime(
                    //
                    // TimeUnit.MILLISECONDS.toNanos(System.currentTimeMillis() + 10000))
                    .build())
            .setTypeFilter(WorkflowTypeFilter.newBuilder().setName("GreetingWorkflow"))
            .build();

Fails with:

INVALID_ARGUMENT: EarliestTime in StartTimeFilter should not be larger than LatestTime.

[alexshtin]

Server doesn't have a concept of "default namespace". Clients are supposed to set default namespace if it is not set. This is what GoSDK does and tctl uses GoSDK for list operations. I would prefer Java and other SDK to do the same.

Dates validator seems to be fixed in #641 and #1631.