viper-data-collection changes

[Simon-Hostettler]

This PR contains code to enable submitting programs to the viper-data-collection backend. These changes should be merged first, since all changes made to the frontends / verifiers depend on them.

Changes made:

• Added requests and upickle as dependencies to serialize and submit programs over http.
• Added a --submitForEvaluation flag to the SilFrontendConfig to get user consent.
• Created ProgramSubmitter implementations which handle data gathering and submission, and which will be used by the frontends / verifiers.

[Simon-Hostettler]

I don't know why a timeout occurred for the test all/third_party/stefan_recent/testTreeWandE1.vpr. Running this code locally, the verification for this test finishes after 10 seconds. Also none of the changes should affect verification in any way.

Edit: Timeout didn't occur on rerun.