dynamodb.table: implement update for global secondary indexes

[muvaf]

Description of your changes

The diff and update methods aren't generated for that field since its name and type is different in UpdateTableInput from CreateTableInput. So, we had to manually implement the whole mechanism.

Fixes a few small things like getting rid of cmpopts for isUpToDate and making sure we strip off the request ID from v1 SDK errors.

Fixes #927

Note that it turned out ReplicaUpdates is only for GlobalTable resource and it's already implemented.

I have:

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

How has this code been tested

Manually with the example YAML by;

• Create a normal table without Global Secondary Index (GSI).
• Add a new GSI.
• Delete the GSI by making that array zero-length.

[muvaf]

@stevendborrelli please take a look

[haarchri]

tested the Ressource LGTM
thanks for UnitTests

[stevendborrelli]

LGTM!

I have been able to test successfully the following:

• Create a Table without Global Secondary Index (GSI).
• Add a GSI & review in the AWS console
• Delete the GSI & review in the AWS console
• Delete the Table & review in AWS console