Support specifying additional AWS IAM trust relationships for roles managed by Otterize

[orishoshan]

Description

Specify the following annotation on a pod to add an additional trust relationship statement:

credentials-operator.otterize.com/additional-role-trust-relationship-statements: '[{"Effect": "Allow", "Principal": {"AWS": "*"}, "Action": ["sts:AssumeRoleWithWebIdentity"]}]'

References

Infrastructure change to support the credentials operator functionality of the same, in otterize/credentials-operator#185.

Testing

• This change adds test coverage for new/changed/fixed functionality

Checklist

• I have added documentation for new/changed functionality in this PR and in github.com/otterize/docs