Add DNS provider for RU Center

[AntonDzyk]

https://nic.ru/

[ldez]

Hello, in order for a PR adding a DNS provider to be accepted, you have to:

• add a description to your PR
• be able to maintain this provider
• have a homogeneous design with the other providers
• add tests (units)

make test

• add tests ("live")
  

  lego/providers/dns/cloudflare/cloudflare_test.go

  Lines 125 to 151 in c938de6

  	func TestLivePresent(t *testing.T) {
  	if !envTest.IsLiveTest() {
  	t.Skip("skipping live test")
  	}
  	envTest.RestoreEnv()
  	provider, err := NewDNSProvider()
  	require.NoError(t, err)
  	err = provider.Present(envTest.GetDomain(), "", "123d==")
  	require.NoError(t, err)
  	}
  	func TestLiveCleanUp(t *testing.T) {
  	if !envTest.IsLiveTest() {
  	t.Skip("skipping live test")
  	}
  	envTest.RestoreEnv()
  	provider, err := NewDNSProvider()
  	require.NoError(t, err)
  	time.Sleep(2 * time.Second)
  	err = provider.CleanUp(envTest.GetDomain(), "", "123d==")
  	require.NoError(t, err)
  	}

make test

• add a provider descriptor
• generate CLI help, documentation, and readme.

make generate-dns

• be able to do: (and put the output of this command to a comment in your PR)

rm -rf .lego

./lego -m your@email.com --dns YOUR_PROVIDER_NAME -d *.example.com -d example.com -s https://acme-staging-v02.api.letsencrypt.org/directory run

Note the wildcard domain is important.

• pass the linter (golangci-lint must be installed):

make checks

• do go mod tidy

[ldez]

Your PR was far away from the design of the other implementations, so I rewrite it and add tests on the client.

You can check my previous comment to know what are the next requirements.

[ldez]

ping @AntonDzyk

[ldez]

@AntonDzyk can you provide the missing information?
#1892 (comment)

[ldez]

ping @AntonDzyk

[ldez]

I'm still waiting for feedback @AntonDzyk.

---

If a user wants to help this PR by testing it, you are welcome to do so.

How to test this PR?

1. You need Go
2. Checkout the PR:

   git clone https://github.com/AntonDzyk/lego.git
   cd lego
   git checkout master

3. Compile lego:
   • if you have make: make build
   • if you don't make make: go build ./cmd/lego -o dist/lego
4. Run the following command with your own information (email, domain, credentials):

   NICRU_USER="<your_user>" \
   NICRU_PASSWORD="<your_password>" \
   NICRU_SERVICE_ID="<service_id>" \
   NICRU_SECRET="<service_secret>" \
   NICRU_SERVICE_NAME="<service_name>" \
   ./dist/lego --dns nicru --domains "*.example.com" -d *.example.com -d example.com -s https://acme-staging-v02.api.letsencrypt.org/directory run

   The wildcard domain is important
5. Before each run of the command, you should clean your local environment:

   rm -rf .lego