[ggj][bazel] build: better bazel imports (#372)

* build: better bazel imports

* fix: more Bazel updates

Co-authored-by: Summer Ji <summerji@google.com>

BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:defs.bzl", "java_binary", "java_proto_library")
 load(
     "//:gapic_generator_java.bzl",
     "google_java_format",

src/main/java/com/google/api/generator/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library", "java_plugin")
+
 package(default_visibility = ["//visibility:public"])
 #package(default_visibility = ["//:__pkg__"])
 

src/main/java/com/google/api/generator/engine/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/engine/ast/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/engine/escaper/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/engine/lexicon/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/engine/writer/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library", "java_proto_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/composer/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/model/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/protoparser/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library", "java_proto_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/protowriter/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/main/java/com/google/api/generator/gapic/utils/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/test/java/com/google/api/generator/engine/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:defs.bzl", "java_test")
 load("//:rules_bazel/java/java_diff_test.bzl", "golden_update")
 
 package(default_visibility = ["//visibility:public"])

src/test/java/com/google/api/generator/engine/ast/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/engine/lexicon/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/engine/writer/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/gapic/composer/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:defs.bzl", "java_proto_library", "java_test")
 load("//:rules_bazel/java/java_diff_test.bzl", "golden_update")
 
 package(default_visibility = ["//visibility:public"])

src/test/java/com/google/api/generator/gapic/model/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/gapic/protoparser/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/gapic/testdata/BUILD.bazel

@@ -1,3 +1,6 @@
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_java//java:defs.bzl", "java_proto_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(

src/test/java/com/google/api/generator/gapic/utils/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_test")
+
 package(default_visibility = ["//visibility:public"])
 
 TESTS = [

src/test/java/com/google/api/generator/test/framework/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
 package(default_visibility = ["//visibility:public"])
 
 filegroup(