chore(inserter): making the inserter package more efficient

[Jacobbrewer1]

Describe your changes

This pull request includes several changes to the inserter package, focusing on improving the validation logic and refactoring the code for better readability and maintainability. The most important changes include updates to the validateSQLGen and validateSQLInsert methods, the addition of new helper methods for field checks, and modifications to the genBatch and GenerateSQL methods.

Validation Improvements:

• inserter/batch.go: Refactored the validateSQLGen and validateSQLInsert methods to use switch statements for better readability and maintainability.

Helper Methods for Field Checks:

• inserter/batch.go: Added new helper methods (checkSkipField, checkSkipTag, checkPrimaryKey, ignoredFieldsCheck, checkIgnoreFunc, checkIgnoredFields) to centralize and simplify field validation logic.

Refactoring and Code Simplification:

• inserter/sql.go: Removed redundant field validation logic from the genBatch method and replaced it with calls to the new helper methods. [1] [2]
• inserter/sql.go: Simplified the GenerateSQL method by optimizing the placeholder generation logic.

Import Adjustments:

• inserter/batch.go and inserter/sql.go: Adjusted imports to include reflect, slices, and strings where necessary and removed unused imports. [1] [2]