Add support for coolify_application resource

[FaureAlexis]

🎯 Scope

Add full support for Coolify applications in the Terraform provider, enabling creation and management of applications via IaC.
Requested in #51

I have tested and deployed an infra with 7 differents applications(laravel, nodejs, nuxtjs) + 2 services (valkey, mysql) using theses changes.

✨ Features

• 6 supported source types:

  • public - Public Git repository
  • private-github-app - Private Git repository via GitHub App
  • private-deploy-key - Private Git repository via Deploy Key
  • dockerfile - Application with custom Dockerfile
  • dockerimage - Docker image from a registry
  • dockercompose - Docker Compose application

• Full CRUD operations: Create, Read, Update, Delete

• Import: Import existing applications by UUID

• Conditional validation: Required fields depend on source_type

• Sensitive data management: Secrets are automatically marked as sensitive

📝 Usage example

resource "coolify_application" "my_app" {
  source_type = "public"
  
  project_uuid     = "xxx"
  server_uuid      = "xxx"
  environment_name = "production"
  
  git_repository = "https://github.com/user/repo"
  git_branch     = "main"
  build_pack     = "nixpacks"
  ports_exposes  = "80"
  
  name = "My Application"
}

📦 Added files

• internal/service/application_model.go - Terraform model and schema
• internal/service/application_resource.go - CRUD implementation
• internal/service/application_resource_test.go - Unit tests
• internal/service/application_resource_acceptance_test.go - Acceptance tests
• examples/resources/coolify_application/* - Examples for each type
• FEATURES_APPLICATION.md - Complete documentation
• USAGE_LOCAL.md - Local usage guide
• scripts/install-local-provider.sh - Installation script (local testing)

🔧 Modified files

• tools/tfplugingen-openapi.yml - Configuration to generate the resource
• internal/provider/provider.go - Resource registration

✅ Tests

• Schema unit tests
• Acceptance tests (create/read/update/delete)
• Compilation without errors
• Conditional validation functional

📚 Documentation

• Examples for each source type in examples/resources/coolify_application/

🚀 How to test

# Install the provider locally
./scripts/install-local-provider.sh

# In your Terraform project (remove .terraform and lock if needed)
terraform init
terraform plan
terraform apply

[FaureAlexis]

Also fixed a bug with applications env : is_build_time is not supported by the API, so if passed as an argument it will not be passed in the Create but will update env var after

[megheaiulian]

This is a very big PR. Its quite hard to review 2k changes.
I think if this was somehow broken in smaller pieces It would make it much more easier to be reviewed and approved.