Upgrade to aws sdk v2

[obeleh]

Fixes #80

I was working on this but our focus changed. But I didn't want to withhold my improvements.
Things left to do:

• Rename the sessions package
• Adjust unit tests not to use sessions anymore

[it-percona-cla]

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1 out of 2 committers have signed the CLA.

✅ denisok
❌ Sjuul Janssen

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[obeleh]

Agreement signed

[obeleh]

I tried clicking on sign again.