Prepare billing pipeline for production

This makes a few cosmetic changes that prepares the pipeline for production.

Namely:
- Converts file names to include the input yearMonth, mostly mirroring the original invoicing pipeline.
- Factors out the yearMonth logic from the reporting module to the more common backend module. We will likely use the default yearMonth logic in other backend tasks (such as spec11 reporting).
- Adds the "withTemplateCompatability" flag to the Bigquery read, which allows multiple uses of the same template.
- Adds the 'billing' task queue, which retries up to 5 times every 3 minutes, which is about the rate we desire for checking if the pipeline is complete.
- Adds a shell 'invoicing upload' class, which tests the retry semantics we want for post-generation work (e-mailing the invoice to crr-tech, and publishing detail reports)

While this cl may look big, it's mostly just a refactor and setting up boilerplate needed to frame the upload logic.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=179849586

javatests/google/registry/reporting/IcannReportingModuleTest.java

@@ -16,18 +16,11 @@ package google.registry.reporting;
 
 import static com.google.common.truth.Truth.assertThat;
 import static google.registry.testing.JUnitBackports.expectThrows;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
 
 import google.registry.reporting.IcannReportingModule.ReportType;
 import google.registry.request.HttpException.BadRequestException;
-import google.registry.testing.FakeClock;
-import google.registry.util.Clock;
 import java.util.Optional;
-import javax.servlet.http.HttpServletRequest;
-import org.joda.time.DateTime;
 import org.joda.time.YearMonth;
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -36,42 +29,6 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class IcannReportingModuleTest {
 
-  HttpServletRequest req = mock(HttpServletRequest.class);
-  Clock clock;
-  @Before
-  public void setUp() {
-    clock = new FakeClock(DateTime.parse("2017-07-01TZ"));
-  }
-
-  @Test
-  public void testEmptyYearMonthParameter_returnsEmptyYearMonthOptional() {
-    when(req.getParameter("yearMonth")).thenReturn("");
-    assertThat(IcannReportingModule.provideYearMonthOptional(req)).isEqualTo(Optional.empty());
-  }
-
-  @Test
-  public void testInvalidYearMonthParameter_throwsException() {
-    when(req.getParameter("yearMonth")).thenReturn("201705");
-    BadRequestException thrown =
-        expectThrows(
-            BadRequestException.class, () -> IcannReportingModule.provideYearMonthOptional(req));
-    assertThat(thrown)
-        .hasMessageThat()
-        .contains("yearMonth must be in yyyy-MM format, got 201705 instead");
-  }
-
-  @Test
-  public void testEmptyYearMonth_returnsLastMonth() {
-    assertThat(IcannReportingModule.provideYearMonth(Optional.empty(), clock))
-        .isEqualTo(new YearMonth(2017, 6));
-  }
-
-  @Test
-  public void testGivenYearMonth_returnsThatMonth() {
-    assertThat(IcannReportingModule.provideYearMonth(Optional.of(new YearMonth(2017, 5)), clock))
-        .isEqualTo(new YearMonth(2017, 5));
-  }
-
   @Test
   public void testEmptySubDir_returnsDefaultSubdir() {
     assertThat(IcannReportingModule.provideSubdir(Optional.empty(), new YearMonth(2017, 6)))