feat: support transactions with validation and authentication

[slesaad]

Issue

https://github.com/NASA-IMPACT/veda-backend/issues/295

What?

• Add transactions extensions from - https://github.com/NASA-IMPACT/veda-backend/pull/276
• Add bulk transactions extension
• Add authentication for all transactions PUT POST endpoints
• Add authentication to openapi docs
• Add request validation to all all transactions PUT POST endpoints

Why?

• To allow stac editing (collection and item) + enable stac-admin

Testing?

• Tested locally as well as deployed to https://stacadmin.openveda.cloud/api/stac/docs

TODO

• [x] Refactor the way env vars are used
• [ ] Remove temporary workflow
• [ ] Fix failing tests

[!WARNING]
Although the validation are integrated well - some validations aren't great (eg - error when datetime is null but start_datetime and end_datetime aren't provided - should be valid). probably has to do with stac-pydantic version

[smohiudd]

Couple comments on this PR:

• how can we address the issue that moving auth to a common directory reduces modularity of the stac and ingest APIs?
• I'm curious about the tradeoff between pystac or STAC pydantic for the validation?

[slesaad]

@smohiudd open to ideas about modularity. we should start using pystac instead of stac_pydantic because it is more comprehensive and robust, but I think that should be a separate effort since ingest API also uses stac_pydantic.