<!-- Describe your changes in detail -->

Connector template code for new connector `Payload`. Check the attached issue for documentation and dashboard.

Ref: https://github.com/juspay/hyperswitch/pull/8500
To implement this **search_filter** feature, you'll need to modify these architectural layers:


**1. Domain Models (Business Logic Types)**
   - `crates/hyperswitch_domain_models/src/configs.rs`

**2. Core Business Logic**
   - `crates/router/src/core/admin.rs`

**3. External Connector Integration**
   - `connector-template/mod.rs`
   - `crates/common_enums/src/connector_enums.rs`
   - `crates/connector_configs/src/connector.rs`
   - ... and 14 more files

**4. Type Definitions**
   - `crates/router/src/types/api.rs`
   - `crates/router/src/types/transformers.rs`

**5. Tests**
   - `config/deployments/integration_test.toml`
   - `loadtest/config/development.toml`

**6. Configuration Files**
   - `config/config.example.toml`
   - `config/deployments/production.toml`
   - `config/deployments/sandbox.toml`
   - ... and 2 more files

**Code Patterns Applied:**
- Define new data structures (10 changes)
- Implement new functions (83 changes)
- Extend existing types with new fields (169 changes)

**Detailed Identifier Changes:**


Commit 7f5ec743:
Files to modify:


**connector-template/mod.rs**
  Modify existing code

**crates/common_enums/src/connector_enums.rs**
  Modify existing code

**crates/connector_configs/src/connector.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors/payload.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors/payload/transformers.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/default_implementations.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/default_implementations_v2.rs**
  Modify existing code

**crates/hyperswitch_domain_models/src/configs.rs**
  Modify existing code

**crates/router/src/connector.rs**
  Modify existing code

**crates/router/src/core/admin.rs**
  Modify existing code

**crates/router/src/types/api.rs**
  Modify existing code

**crates/router/src/types/transformers.rs**
  Modify existing code

**crates/router/tests/connectors/main.rs**
  Modify existing code

**crates/router/tests/connectors/payload.rs**
  Modify existing code

**crates/test_utils/src/connector_auth.rs**
  Modify existing code
{"pr_number": 8526, "pr_title": "feat(connector): [payload] template code", "merged_at": "2025-07-03T09:25:37Z", "intent": {"feature_type": "search_filter", "action": "add_feature", "entities": ["connector"]}, "hierarchy": {"domain": ["crates/hyperswitch_domain_models/src/configs.rs"], "core_business": ["crates/router/src/core/admin.rs"], "connectors": ["connector-template/mod.rs", "crates/common_enums/src/connector_enums.rs", "crates/connector_configs/src/connector.rs", "crates/connector_configs/toml/development.toml", "crates/connector_configs/toml/production.toml", "crates/connector_configs/toml/sandbox.toml", "crates/hyperswitch_connectors/src/connectors.rs", "crates/hyperswitch_connectors/src/connectors/payload.rs", "crates/hyperswitch_connectors/src/connectors/payload/transformers.rs", "crates/hyperswitch_connectors/src/default_implementations.rs", "crates/hyperswitch_connectors/src/default_implementations_v2.rs", "crates/router/src/connector.rs", "crates/router/tests/connectors/main.rs", "crates/router/tests/connectors/payload.rs", "crates/router/tests/connectors/sample_auth.toml", "crates/test_utils/src/connector_auth.rs", "scripts/add_connector.sh"], "types": ["crates/router/src/types/api.rs", "crates/router/src/types/transformers.rs"], "tests": ["config/deployments/integration_test.toml", "loadtest/config/development.toml"], "config": ["config/config.example.toml", "config/deployments/production.toml", "config/deployments/sandbox.toml", "config/development.toml", "config/docker_compose.toml"]}, "change_types": {"structs_added": 10, "functions_added": 83, "enums_added": 2, "fields_added": 169, "imports_added": 21}, "has_identifier_data": true, "commits_matched": 1, "match_method": "pr_number"}