✨ (FieldMappingTool): add new field mapping classes for Azure DevOps

Introduce new field mapping classes: `FieldClearMap`, `FieldLiteralMap`, `FieldMapBase`, `FieldMergeMap`, and `FieldSkipMap`. These classes provide various field mapping functionalities for Azure DevOps work item migration.

- `FieldClearMap`: Clears the value of a specified field in the target work item.
- `FieldLiteralMap`: Sets a specified field in the target work item to a literal value.
- `FieldMapBase`: Serves as the base class for all field mapping operations.
- `FieldMergeMap`: Merges multiple source fields into a single target field using a specified format.
- `FieldSkipMap`: Skips the mapping of a specified field if certain conditions are met.

These changes enhance the flexibility and functionality of the field mapping tool, allowing for more complex and customizable migration scenarios.

✨ (FieldMappingTool): add new field mapping classes for Azure DevOps

Introduce new classes to support various field mapping strategies:
- `FieldToFieldMap`: Maps a field from source to target.
- `FieldToTagFieldMap`: Maps a field from source to target tags.
- `FieldValueMap`: Maps field values with specific value mappings.
- `FieldValuetoTagMap`: Maps field values to tags based on patterns.
- `FieldtoFieldMultiMap`: Maps multiple fields from source to target.

These changes enhance the flexibility and functionality of the field mapping tool, allowing for more complex and varied migration scenarios.

✨ (FieldMappingTool): add new field mapping tools for Azure DevOps

Introduce four new field mapping tools: `MultiValueConditionalMap`, `NodePathNotAnchoredException`, `RegexFieldMap`, and `TreeToTagFieldMap`. These tools enhance the flexibility and functionality of field mapping in Azure DevOps migrations.

- `MultiValueConditionalMap` allows conditional field mapping based on multiple source field values.
- `NodePathNotAnchoredException` provides a custom exception for node path issues.
- `RegexFieldMap` enables field value transformation using regular expressions.
- `TreeToTagFieldMap` converts tree structures into tags for better organization.

These additions aim to improve the robustness and versatility of the migration tools, addressing various use cases and scenarios encountered during migrations.