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/go/mirko/tests/sql/BUILD.bazel b/go/mirko/tests/sql/BUILD.bazel
index 5831dcd..aab01df 100644
--- a/go/mirko/tests/sql/BUILD.bazel
+++ b/go/mirko/tests/sql/BUILD.bazel
@@ -4,7 +4,16 @@
     name = "go_default_test",
     srcs = ["sql_test.go"],
     deps = [
-        "//go/mirko/tests/sql/migrations:go_default_library",
-        "@com_github_golang_migrate_migrate_v4//database/sqlite3:go_default_library",
+        "//go/mirko/tests/sql/migrations",
+        "@com_github_golang_migrate_migrate_v4//database/sqlite3",
+    ],
+)
+
+go_test(
+    name = "sql_test",
+    srcs = ["sql_test.go"],
+    deps = [
+        "//go/mirko/tests/sql/migrations",
+        "@com_github_golang_migrate_migrate_v4//database/sqlite3",
     ],
 )