go: re-do the entire thing

This is a mega-change, but attempting to split this up further is
probably not worth the effort.

Summary:

1. Bump up bazel, rules_go, and others.
2. Switch to new go target naming (bye bye go_default_library)
3. Move go deps to go.mod/go.sum, use make gazelle generate from that
4. Bump up Python deps a bit

And also whatever was required to actually get things to work - loads of
small useless changes.

Tested to work on NixOS and Ubuntu 20.04:

   $ bazel build //...
   $ bazel test //...

Change-Id: I8364bdaa1406b9ae4d0385a6b607f3e7989f98a9
Reviewed-on: https://gerrit.hackerspace.pl/c/hscloud/+/1583
Reviewed-by: q3k <q3k@hackerspace.pl>
diff --git a/devtools/depotview/service/BUILD.bazel b/devtools/depotview/service/BUILD.bazel
index 056ec30..b2f70a6 100644
--- a/devtools/depotview/service/BUILD.bazel
+++ b/devtools/depotview/service/BUILD.bazel
@@ -1,7 +1,7 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
-    name = "go_default_library",
+    name = "service",
     srcs = [
         "gerrit.go",
         "service.go",
@@ -9,23 +9,23 @@
     importpath = "code.hackerspace.pl/hscloud/devtools/depotview/service",
     visibility = ["//visibility:public"],
     deps = [
-        "//devtools/depotview/proto:go_default_library",
-        "@com_github_go_git_go_git_v5//:go_default_library",
-        "@com_github_go_git_go_git_v5//config:go_default_library",
-        "@com_github_go_git_go_git_v5//plumbing:go_default_library",
-        "@com_github_go_git_go_git_v5//plumbing/filemode:go_default_library",
-        "@com_github_go_git_go_git_v5//plumbing/object:go_default_library",
-        "@com_github_go_git_go_git_v5//storage:go_default_library",
-        "@com_github_go_git_go_git_v5//storage/memory:go_default_library",
-        "@com_github_golang_glog//:go_default_library",
-        "@org_golang_google_grpc//codes:go_default_library",
-        "@org_golang_google_grpc//status:go_default_library",
+        "//devtools/depotview/proto",
+        "@com_github_go_git_go_git_v5//:go-git",
+        "@com_github_go_git_go_git_v5//config",
+        "@com_github_go_git_go_git_v5//plumbing",
+        "@com_github_go_git_go_git_v5//plumbing/filemode",
+        "@com_github_go_git_go_git_v5//plumbing/object",
+        "@com_github_go_git_go_git_v5//storage",
+        "@com_github_go_git_go_git_v5//storage/memory",
+        "@com_github_golang_glog//:glog",
+        "@org_golang_google_grpc//codes",
+        "@org_golang_google_grpc//status",
     ],
 )
 
 go_test(
-    name = "go_default_test",
+    name = "service_test",
     srcs = ["service_test.go"],
-    embed = [":go_default_library"],
-    deps = ["//devtools/depotview/proto:go_default_library"],
+    embed = [":service"],
+    deps = ["//devtools/depotview/proto"],
 )