[API] Add support to export faceted search result with template file

[ekazachkova]

Background
At the moment, Cloud Pipeline does not allow to export facet search result with predefined format and it would be nice to support it.

Approach

• Introduce a new system preference search.export.template.mapping with the following format:

{
    "TemplateName": {
        "save_to": "<...>",  # optional, cloud path to save search report
        "friendly_name": "<..>",  # optional, short file description
        "template_path": "<...>",   # required, path to template file that shall be available for API
        "permissions": [{
            "name": "<..>",  # user or group name
            "principal": true,  # boolean, 'true' for users 'false' for groups
        }, ... ],
        "mapping": {  # required, describes template columns mappings
            "Sheet1": [ # the name of the sheet
                    {
                        "column": "AA",  # string, indicates an column index
                        "start_row": "2",  # 1-base start index for rows
                        "value": "{Placeholder1}  some text {Placeholder2}", # content for cells with placeholders to replace
                        "unique": false,  # optional, bool, default: false, indicates if values in this column shall be unique
                        "keep_unresolved": false,  #  optional, bool, default: false, indicates if unresolved placeholders shall be left as is
                                                   #  if false unresolved placeholders shall be replaced with empty strings
                    }, {
                    }, ...
            ]
        }
    }
}

Configuration field save_to shall support placeholders:
- Template_ID - the name of template
- Export_Date - the current date
- Export_Date:yyyyMMdd-HH:mm:ss - current date with datetime format
- User - the name of the user initiated template generation
Example: s3://bucket_name/{User}/{Export_Date:yyyyMMdd-HH:mm:ss}/{Template_ID}.xls

• Introduce a new API method POST /search/facet/export/templates that streams template content. Request parameters:
  • templateId - required, the name of template (the key from template configuration)
  • fileName - optional, the name of the result report file. If not specified a file name <TemplateId>-<DateTime>.xls shall be generated.
• Introduce a new API method POST /search/facet/export/templates/save that saves search results report to save_to path from template configuration. Request params:
  • templateId - required, the name of template (the key from template configuration)
    Request body:

{
     "fullPath": "s3://bucket_name/folder/export.xls",
     "storageId": 1,  # this storage registered by path `s3://bucket_name/folder/`
     "storagePath": "export.xls" 
}

Also, it would be nice to support storage files filter: if user manually specified multiple storage files, only this files shall be present in export reports. A new field files shall be added to request body:

{ ....,
    "files": [
        {
            "path": "file1.txt",  # path from facet response
            "storageId": 1  # parentId from facet response
        },
        {
            "path": "file2.txt",
            "storageId": 2
        },
        {
            "path": "file3.txt",
            "storageId": 3
        }
    ], ...
}

If files provides query and filters shall be ignored.