Add amount-join support in client

Also adapted existing EIP-712 filters test files

tests/ragger/eip712_input_files/00-simple_mail-filter.json

@@ -1,7 +1,13 @@
 {
     "name": "Test JSON",
     "fields": {
-        "from.name": "From",
-        "to.name" : "To"
+        "from.name": {
+            "type": "raw",
+            "name": "From"
+        },
+        "to.name": {
+            "type": "raw",
+            "name": "To"
+        }
     }
-}
+}

tests/ragger/eip712_input_files/08-opensea-filter.json

@@ -1,9 +1,21 @@
 {
     "name": "OpenSea",
     "fields": {
-        "maker": "Maker",
-        "taker": "Taker",
-        "basePrice": "Base Price",
-        "expirationTime": "Expiration Time"
+        "maker": {
+            "type": "raw",
+            "name": "Maker"
+        },
+        "taker": {
+            "type": "raw",
+            "name": "Taker"
+        },
+        "basePrice": {
+            "type": "raw",
+            "name": "Base Price"
+        },
+        "expirationTime": {
+            "type": "raw",
+            "name": "Expiration Time"
+        }
     }
-}
+}

tests/ragger/eip712_input_files/11-complex_structs-filter.json

@@ -1,9 +1,21 @@
 {
     "name": "Depthy Test",
     "fields": {
-        "contents": "Message",
-        "from.name": "Sender",
-        "to.members.[].name": "Recipient",
-        "attach.list.[].name": "Attachment"
+        "contents": {
+            "type": "raw",
+            "name": "Message"
+        },
+        "from.name": {
+            "type": "raw",
+            "name": "Sender"
+        },
+        "to.members.[].name": {
+            "type": "raw",
+            "name": "Recipient"
+        },
+        "attach.list.[].name": {
+            "type": "raw",
+            "name": "Attachment"
+        }
     }
-}
+}

tests/ragger/eip712_input_files/12-sign_in-filter.json

@@ -1,7 +1,13 @@
 {
     "name": "Ethereum sign-in",
     "fields": {
-        "curDate": "Timestamp",
-        "id": "Identifier"
+        "curDate": {
+            "type": "raw",
+            "name": "Timestamp"
+        },
+        "id": {
+            "type": "raw",
+            "name": "Identifier"
+        }
     }
-}
+}