Allow generating signed PUT urls for objects

[camol]

This PR adds the possibility to generate signed PUT urls for uploading files.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ camol
❌ bosen
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[coveralls]

Coverage decreased (-0.002%) to 98.041% when pulling 377e3a4 on AcornsGrowAU:master into fe06665 on aliyun:master.

[coveralls]

Coverage decreased (-0.002%) to 98.041% when pulling 377e3a4 on AcornsGrowAU:master into fe06665 on aliyun:master.

[camol]

The tests are failing because of the missing bundler for some of the Ruby versions so it seems that it is not related to the change that I'm introducing.