merge sites and observations API's

[tinashechiraya]

We need to merge the API FBIS is consuming and the one created for Digital Twin into one since they both serve the same purpose.
The outcome will be the API FBIS is consuming will be extended

• usage of a token to access API
• filtering by dates functionality
• downloadable images url
• expected data format
• updated tests

[amyburness]

@tinashechiraya

We need to ensure the build is Swagger compliment @dimasciput to review and guide on this (please add it as a task).