Middleman template project: Add GitLab CI configuration for testing, building and deploying it to GitLab Pages

Job To Be Done

Configure the Middleman template project to run on GitLab CI. The CI configuration should:

• Run the tests
• Build the project
• Deploy the project to GitLab Pages

Tasks

- [ ] Add configuration file to run the tests

• Add configuration file to build the project - gitlab-org/project-templates/static-site-editor-middleman!2 (merged)
• Add configuration file to deploy the project to Gitlab Pages - gitlab-org/project-templates/static-site-editor-middleman!2 (merged)