erp5_stripe: Use activity to store stripe session in ERP5

We set the module as a source to acquire roles. Also, we need to store request and response in HTTP Exchange.

This merge request is to fix ec4a3f9d

See merge request !1771
8 jobs for master in 0 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:00:27

passed ERP5.PerformanceTest-Master

00:26:57

passed ERP5.UnitTest-Master

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failed ERP5.UnitTest-Zope2

02:27:07

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:11

passed SlapOS.Eggs.UnitTest-Master.Python3

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passed Wendelin.UnitTest-Master

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passed Wendelin.UnitTest-Master

00:48:17