feat: service and metadata fields add to CSV export

[Mahiro-T]

Problem

Added Service Name and Metadata as I wanted them when downloading CSV from Inventory on Komiser.
I know you can sort by Service Name, etc. on Komiser, but I would like to do this on CSV as well.
I also added Metadata because I want to see what is associated with a resource such as an Instance (e.g. EBS).

Solution

get datas and headers are added to the CSV generation points(handlers/csv_handler.go) in the backend.

Changes Made

• Get metadata and service name from data fetching from database.

How to Test

I downloaded csv from komiser frontend.

Screenshots

Downloaded csv's screenshot. (Account ID, etc. are rewritten manually.)

Notes

Checklist

• Code follows the contributing guidelines
• Changes have been thoroughly tested
• Documentation has been updated, if necessary (I searched the documentation and could not find any mention of CSV.)
• Any dependencies have been added to the project, if necessary

Reviewers

@[username of the reviewer]

[github-actions]

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