feat: refactor KsDecode to handle stringData and data nodes

[yxxhero]

This pull request includes several changes to improve code readability, enhance error handling, and update functionality in the cmd/vals, pkg/log, and pkg/providers/vault packages. The most important changes include updating variable names for clarity, adding error handling for fmt.Fprintln and fmt.Fprintf, and modifying the KsDecode function to handle both data and stringData nodes.

Improvements to readability and error handling:

• cmd/vals/main.go: Updated variable names in the KsDecode function to make the code more understandable and added comments to explain the logic. [1] [2] [3]
• cmd/vals/main.go: Added error handling for fmt.Fprintln to ignore returned values.
• io.go: Added error handling for fmt.Fprintln to ignore returned values. [1] [2]
• pkg/log/log.go: Added error handling for fmt.Fprintf to ignore returned values.

Functional updates:

• cmd/vals/main.go: Modified the KsDecode function to handle both data and stringData nodes, ensuring proper decoding and merging of these nodes. [1] [2]
• cmd/vals/main_test.go: Updated test cases to include stringData nodes, ensuring the new functionality is tested.

Other changes:

• pkg/providers/vault/kv_helper.go: Replaced hardcoded status code 404 with http.StatusNotFound for better readability and maintainability.
• pkg/providers/vault/kv_helper.go: Added net/http import to support the status code change.

[yxxhero]

#520

[yxxhero]

@mumoshu

[mumoshu]

LGTM! Thanks for your continued effort @yxxhero!