[parachain-template] pallet configurations into `mod configs` (#3809)

This PR introduces a refactor of the parachain runtime configuration by
consolidating all pallet configurations into a new module named
`configs`. This change aims to improve the readability and
maintainability of the runtime configuration by centralizing all
configuration parameters.

## Changes
- **Creation of `configs.rs`**: A new file `configs.rs` has been added
under `templates/parachain/runtime/src/`, containing all the runtime
configurations previously scattered across `lib.rs`.
- **Refactoring of `lib.rs`**: The `lib.rs` file has been significantly
slimmed down by removing the inline pallet configurations and importing
them from `configs.rs` instead.
- **Optimization of Import Statements**: Reorganized import statements
to clarify the runtime's dependency structure.

### Benefits
- **Improved Readability**: With configurations being centralized,
developers can now easily locate and review runtime parameters without
navigating through the `lib.rs` file.

This refactor does not introduce any changes to the runtime logic but
improves the project structure for better development experience.

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Co-authored-by: Kian Paimani <[email protected]>