Replace RDS from AWS-SDK with @aws-sdk/client-rds

[kr8n3r]

What

Replace whole of aws-sdk in favour of the modular @aws-sdk/client-rds modular package. This will require a bit of a rewrite where we use it

• src/components/services/controllers.tsx
• src/components/services/views.tsx
• src/components/services/controllers.mocked.test.tsx

Why

aws-sdk is v2 and it's a monolith package. V3 has been split into modular packages and we're already using those as of #1742
Replacing this remaining instance will allow as to fully remove v2 of aws-sdk.

It’s done when

• aws-sdk and @types/aws-sdk are removed
• @aws-sdk/client-rds is used for RDS stuff

If we don’t do this

• we'll be using v2 and v3 and Amazon will at some point deprecate v2