Change time dependent trade limits

This is in accordance with bisq-network/proposals#264

Any account type that doesn't need signing can now trade the full
amount immediately, same goes for signed type accounts that are
selling.

Signed type accounts that are buying now has minimum limit (0.01 BTC) up until
30 days after getting signed, then the limit is increased to 0.5 times the max
limit (0.125 BTC) and after 60 days they get the full limits (0.25 BTC).

core/src/main/java/bisq/core/account/witness/AccountAgeWitnessService.java

@@ -408,17 +408,7 @@ private double signedBuyFactor(AccountAge accountAgeCategory) {
     }
 
     private double normalFactor(AccountAge accountAgeCategory) {
-        switch (accountAgeCategory) {
-            case TWO_MONTHS_OR_MORE:
-                return 1;
-            case ONE_TO_TWO_MONTHS:
-                return 0.5;
-            case LESS_ONE_MONTH:
-            case UNVERIFIED:
-                return 0.25;
-            default:
-        }
-        return 0;
+        return 1;
     }
 
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