Allocate quota for membership instead of identity

Reminder:
Currently, no fees are applied when the network is under normal usage. In cases of high demand, transaction fees are introduced. For users with an identity, these fees are refunded through a quota system that starts accumulating from the moment the identity is created.

Changes in this MR:
This merge request modifies the quota accumulation and refund prerequisites:

• Only members are now eligible for refunds.
• Quotas begin accumulating when an identity becomes a member, rather than at identity creation.
• If an identity's status changes to NotMember (e.g., excluded), refunds are no longer possible.
• As before, quotas are removed when membership is revoked.
• Revoked identities will unlink their accounts.

---

• Revoked identities should unlink their account.
• Allocate quota for Membership fix #247 (closed).
• Add tests.
• Upgrade the polkadot-sdk crate dependency. Note that currently the project does not compile with all dependencies upgraded due to a conflict in the SDK.

end2end-tests/cucumber-features/distance_fail.feature

@@ -31,12 +31,14 @@ Feature: Distance fail
     When bob certifies ferdie
     Then ferdie should be certified by bob
     Then ferdie should have 0 ĞD reserved
-    Then ferdie should have 1449 cĞD
+    # 700 + 750 - 2(one transaction fee, not a member yet)
+    Then ferdie should have 1448 cĞD
     When ferdie requests distance evaluation
     Then ferdie should have 10 ĞD reserved
-    Then ferdie should have 449 cĞD
+    # 1448 - 1000 - 2(one transaction fee, not a member yet)
+    Then ferdie should have 446 cĞD
     When 7 blocks later
-    Then treasury should contain 102 cĞD
+    Then treasury should contain 105 cĞD
     When alice runs distance oracle
     When 7 blocks later
     Then ferdie should be certified by alice
@@ -45,6 +47,6 @@ Feature: Distance fail
     Then ferdie identity should be unvalidated
     # Ferdie got his reserve slashed
     Then ferdie should have 0 ĞD reserved
-    Then ferdie should have 449 cĞD
+    Then ferdie should have 446 cĞD
     # Slashed amount is transfered to treasury
-    Then treasury should contain 1102 cĞD
+    Then treasury should contain 1105 cĞD