Add an operator page to show application counts of all projects

[nghialv]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #1511

Does this PR introduce a user-facing change?:

The operator now can see the number of application of projects

[pipecd-bot]

The following files are not gofmt-ed. By commenting /golinter fmt, the formatted one will be appended to this pull request automatically.

pkg/app/ops/handler/handler_test.go

--- pkg/app/ops/handler/handler_test.go.orig
+++ pkg/app/ops/handler/handler_test.go
@@ -18,8 +18,9 @@
 	"bytes"
 	"testing"
 
-	"github.com/pipe-cd/pipe/pkg/model"
 	"github.com/stretchr/testify/assert"
+
+	"github.com/pipe-cd/pipe/pkg/model"
 )
 
 func TestMakeApplicationCounts(t *testing.T) {

[pipecd-bot]

Code coverage for golang is 32.62%. This pull request decreases coverage by -0.28%.

File	Function	Base	Head	Diff
pkg/app/ops/handler/handler.go	NewHandler	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.Run	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.run	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.stop	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.handleTop	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.handleListProjects	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.handleAddProject	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	Handler.handleApplicationCounts	--	0.00%	+0.00%
pkg/app/ops/handler/handler.go	groupApplicationCounts	--	100.00%	+100.00%

[khanhtc1202]

Nice
/lgtm

[nakabonne]

Cool

[pipecd-bot]

This pull request is APPROVED by nakabonne.

Approvers can cancel the approval by writing /approve cancel in a comment. Any additional commits also will change this pull request to be not-approved.

[pipecd-bot]

failed to handle template rule manifests

Details

Error: unabled to render file: manifests/pipecd/prom-rules/alerting_rules.yml, err: template: template-plugin:11: undefined variable "$labels"