Upload images

I propose to upload our images to a different branch of project repository. Reasons:
- persistent files after redeploy
- simulating upload to external storage

[Info about sending http request in java](https://attacomsian.com/blog/http-requests-resttemplate-spring-boot)

[GitHub api to upload file](https://docs.github.com/en/rest/repos/contents?apiVersion=2022-11-28#create-or-update-file-contents)