Jenkins Configuration as Code and Bitbucket Server

Question

I'm working on our Jenkins setup and I want to go for the configuration as code approach. We want to generate different variants of Jenkins masters using Terraform in Azure cloud and configure them with yaml. I found the configuration-as-code-plugin which I think could be a good solution. The problem is that I cannot find meaningful documentation and references for the single plugins to be configured in yaml. There are some examples but the they are just not enough.

What I tried to do is to setup a Jenkins master to use Bitbucket the traditional way and then with the plugin I extracted the actual configuration as a yaml file:

...
- credentials:
      - bitbucketToken:
          description: "Bitbucket token"
          id: "60840b9a-636b-4be7-a9c8-81cc7fab59a9"
          secret: "{AQAAABAAAAAwK+Yc/xxxxxxxxx/xxxxxxxxxxxxxxxxxxxxx/xxxxxxxxxxxxxxxxx==}"
...
bitbucketPluginConfiguration:
    serverList:
    - adminCredentialsId: "60840b9a-636b-4be7-a9c8-81cc7fab59a9"
      baseUrl: "http://localhost:7990/"
      id: "zzzzzz-zzzzz-zzzz-zzzzzz-zzzzzzzz"
      serverName: "Bitbucket Server"
...

most of the entries are clear to me, but two are strange:

"secret" and the two "id"s

From where are the "id"s and the "secret" coming? Are they automatically generated by Jenkins? How can I create/get them without the need of having a running Jenkins? Is there any reference about these parameters?

Thanks in advance for your help