proto: add proto files for ibc unblock (#4853)

## Description

these proto files are meant to help unblock ibc in their quest of migrating the ibc module to proto.

Closes: #XXX

libs/bits/bit_array_test.go

@@ -265,3 +265,26 @@ func TestJSONMarshalUnmarshal(t *testing.T) {
 		})
 	}
 }
+
+func TestBitArrayProtoBuf(t *testing.T) {
+	testCases := []struct {
+		msg     string
+		bA1     *BitArray
+		expPass bool
+	}{
+		{"success empty", &BitArray{}, true},
+		{"success", NewBitArray(1), true},
+		{"success", NewBitArray(2), true},
+		{"negative", NewBitArray(-1), false},
+	}
+	for _, tc := range testCases {
+		protoBA := tc.bA1.ToProto()
+		ba := new(BitArray)
+		ba.FromProto(protoBA)
+		if tc.expPass {
+			require.Equal(t, tc.bA1, ba, tc.msg)
+		} else {
+			require.NotEqual(t, tc.bA1, ba, tc.msg)
+		}
+	}
+}