docs: update default network_params.json file (#197)

- reduce capella fork epoch to 0 from 2
- indent mev_params for easier readability
- add "mev_flood_seconds_per_bundle": 15,
- add "launch_custom_flood": false

---------
Co-authored-by: Gyanendra Mishra <anomaly.the@gmail.com>

network_params.json

@@ -21,8 +21,8 @@
 		"slots_per_epoch": 32,
 		"num_validator_keys_per_node": 64,
 		"preregistered_validator_keys_mnemonic": "giant issue aisle success illegal bike spike question tent bar rely arctic volcano long crawl hungry vocal artwork sniff fantasy very lucky have athlete",
-        "capella_fork_epoch": 2,
-        "deneb_fork_epoch": 4
+		"capella_fork_epoch": 0,
+		"deneb_fork_epoch": 500
 	},
 	"launch_additional_services": true,
 	"wait_for_finalization": false,
@@ -31,7 +31,7 @@
 	"global_client_log_level": "info",
 	"snooper_enabled": false,
 	"parallel_keystore_generation": false,
-    "mev_type": "None",
+	"mev_type": null,
 	"mev_params": {
 		"mev_relay_image": "flashbots/mev-boost-relay",
 		"mev_relay_api_extra_args": [],
@@ -39,6 +39,8 @@
 		"mev_relay_website_extra_args": [],
 		"mev_builder_extra_args": [],
 		"mev_flood_image": "flashbots/mev-flood",
-		"mev_flood_extra_args": []
+		"mev_flood_extra_args": [],
+		"mev_flood_seconds_per_bundle": 15,
+		"launch_custom_flood": false
 	}
 }