Make an image from stac-fastapi-pgstac and push it to the docker hub

The objective of this job is to generate a docker image using stac-fastapi-pgstac and thereafter push it to the docker hub. This approach aims to replace the present method of building the docker image in each INSUPDDEL4STAC pipeline run. Instead, the image will be pulled once for unit testing purposes. The version of this docker image will be modified through the process of updating on stac-fastapi-pgstac.