feat(skip): [#233] removed managedPolicyArns from iam role

[haarchri]

Signed-off-by: Christopher Haar chhaar30@googlemail.com

Description of your changes

removed managedPolicyArns field to use multiple rolepolicyattachments

Fixes #233

I have:

• [x] Read and followed Crossplane's contribution process.
• [x] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

added a iam role added multiple rolepolicyattachments

NAME                                                   READY   SYNCED   EXTERNAL-NAME           AGE
role.iam.aws.jet.crossplane.io/sop-prod-grafana-role   True    True     sop-prod-grafana-role   1d
NAME                                                                            READY   SYNCED   EXTERNAL-NAME                                      AGE
rolepolicyattachment.iam.aws.jet.crossplane.io/test1-dr9p7-42p4f                True   True     sop-prod-grafana-role-20220909162408677200000001   10h
rolepolicyattachment.iam.aws.jet.crossplane.io/test2-8hg7t-92s7z                True   True     sop-prod-grafana-role-20220909162149725800000001   10h
rolepolicyattachment.iam.aws.jet.crossplane.io/test3-fgjlt-xl8mk                True   True     sop-prod-grafana-role-20220909162437312700000001   10h
rolepolicyattachment.iam.aws.jet.crossplane.io/test4-fpdpz-lt9js                True   True     sop-prod-grafana-role-20220909162506086200000001   10h
rolepolicyattachment.iam.aws.jet.crossplane.io/test5-5zb25-5zr6h                True   True     sop-prod-grafana-role-20220909162217975800000001   10h