Support external application project integrations

### What problem are you facing?

It is currently not possible to create / configure (external) application integrations using the crossplane provider.
I would love to have them reconciled to not worry about my users changing the settings

I'd like to be able to set them using my kubernetes CRD.

### How could Crossplane help solve your problem?

Could add CRDs similar to terraform:

- [ ] [Custom issue tracker](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_custom_issue_tracker)
- [ ] [Emails on push](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_emails_on_push) https://github.com/crossplane-contrib/provider-gitlab/issues/278
- [ ] [External Wiki](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_external_wiki)
- [ ] [GitHub](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_github) https://github.com/crossplane-contrib/provider-gitlab/issues/289
- [ ] [Harbor](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_harbor)
- [ ] [Jenkins](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_jenkins)
- [ ] [Jira](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_jira)
- [ ] [Mattermost](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_mattermost) crossplane-contrib/provider-argocd#268
- [ ] [Microsoft Teams](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_microsoft_teams)
- [ ] [Pipelines email](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_pipelines_email) https://github.com/crossplane-contrib/provider-gitlab/issues/288
- [ ] [Redmine](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_redmine)
- [ ] [Telegram](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_telegram)
- [ ] [Youtrack](https://registry.terraform.io/providers/gitlabhq/gitlab/latest/docs/resources/project_integration_youtrack)

Start by reviewing the linked Terraform resources for the listed project integrations and the related provider-gitlab issues 278, 288, and 289. The issue does not name provider files or tests; done would mean selected integration CRDs can configure and reconcile the corresponding GitLab project settings.

Written by the indexing model from the issue text.