Scoru,Proto: timeout period as a protocol constant

Context

Partially address #2902 (closed). It lacks the thought of a correct value, the first step however is to use the same values for challenge_window_in_blocks and timeout_period_in_blocks.

Manually testing the MR

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Checklist

• n/a Document the interface of any function added or modified (see the coding guidelines)
• n/a Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• n/a For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR