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/cluster/clustercfg/BUILD b/cluster/clustercfg/BUILD
index e7b308e..d81a947 100644
--- a/cluster/clustercfg/BUILD
+++ b/cluster/clustercfg/BUILD
@@ -1,7 +1,7 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
 
 go_library(
-    name = "go_default_library",
+    name = "clustercfg_lib",
     srcs = [
         "cmd_admincreds.go",
         "cmd_gencerts.go",
@@ -10,16 +10,16 @@
     importpath = "code.hackerspace.pl/hscloud/cluster/clustercfg",
     visibility = ["//visibility:private"],
     deps = [
-        "//cluster/clustercfg/certs:go_default_library",
-        "//go/workspace:go_default_library",
-        "@com_github_spf13_cobra//:go_default_library",
-        "@io_k8s_client_go//tools/clientcmd:go_default_library",
-        "@io_k8s_client_go//tools/clientcmd/api:go_default_library",
+        "//cluster/clustercfg/certs",
+        "//go/workspace",
+        "@com_github_spf13_cobra//:cobra",
+        "@io_k8s_client_go//tools/clientcmd",
+        "@io_k8s_client_go//tools/clientcmd/api",
     ],
 )
 
 go_binary(
     name = "clustercfg",
-    embed = [":go_default_library"],
+    embed = [":clustercfg_lib"],
     visibility = ["//visibility:public"],
 )