Migrate To Backblaze B2

[brarsanmol]

Hi folks,

This issue is just a space for discussion on migrating to Backblaze B2 from GCP for resumes.

• This will save cost.
• The API/Integration is much simpler.

cc: @krubenok

[krubenok]

I think similarly to the emails since it's an S3 compatible API the actual B2-ness could be abstracted away so that we support any S3 API-compatible storage provider. Cloudflare R2 would be another option to consider in future when it's available https://blog.cloudflare.com/introducing-r2-object-storage/