feat(partition_table): Update partition table script and OTA example

1. APP binary supports 4KB align instead of 64KB align

2. Add options to sdkconfig.defaults:
2.1. using 1MB flash
2.2. use custom partition table "partitions_two_ota.1MB.mini.csv"
2.3. custom partition table base address is 0x4000

3. "make ota flash" using APP1_OFFSET as app downloading address

components/partition_table/gen_esp32part.py

@@ -163,7 +163,7 @@ class PartitionDefinition(object):
     MAGIC_BYTES = b"\xAA\x50"
 
     ALIGNMENT = {
-        APP_TYPE : 0x10000,
+        APP_TYPE : 0x1000,
         DATA_TYPE : 0x04,
     }