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/prodvider/service.go b/cluster/prodvider/service.go
index 19f70ed..21b5f57 100644
--- a/cluster/prodvider/service.go
+++ b/cluster/prodvider/service.go
@@ -7,10 +7,10 @@
 	"regexp"
 	"strings"
 
+	ldap "github.com/go-ldap/ldap/v3"
 	"github.com/golang/glog"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	ldap "gopkg.in/ldap.v3"
 
 	pb "code.hackerspace.pl/hscloud/cluster/prodvider/proto"
 )