feat: ensure relative timestamps

[xorsal]

🤖 Linear

Closes OPO-650

Esentially this PR changes the definition of some parameters from being a timestamp to be a number of seconds.

This PR will introduce duplicate calls in some modules.
For example the internal function _validateDispute in Validator.sol does the following check:

    if (ORACLE.disputeCreatedAt(_disputeId) == 0) revert Validator_InvalidDispute();

and now some parts of the dispute modules need to query the dispute creation time to verify if a given dispute is within the escalation window. As a result, any function that uses _validateDispute and also queries the dispute's creation time will make the same call twice.
I can will make another PR to fix this problem later.

---

Another thing to consider is startTime from Escalation struct in IERC20ResolutionModule.

  /**
   * @notice Escalation data for a dispute
   * @param startTime The timestamp at which the dispute was escalated
   * @param totalVotes The total amount of votes cast for the dispute
   */
  struct Escalation {
    uint256 startTime;
    uint256 totalVotes;
  }

This could be redefined as something like "the number of seconds after the creation of the dispute when it was escalated".

[linear]

OPO-650 Ensure relative values are used for timestamps

[github-actions]

Preview: https://prophet-modules-2ge5nkqvz-defi-wonderland.vercel.app

[github-actions]

Preview: https://prophet-modules-b4vkv4qia-defi-wonderland.vercel.app