feat: Add dev mode in dingo

[arepala-uml]

1. Added dev mode support via command line flags (--dev-mode), YAML config files (devMode: true) with proper precedence handling.
2. Modified peer governor to skip outbound connections when dev mode is enabled.
3. Updated test files to handle new dev mode parameter, added comprehensive test coverage, and updated dingo.yaml.example configuration files with proper documentation.

Closes #808

[arepala-uml]

Tested all the cases like

1. Checked running dingo with dev-mode as True from command line and we can see the skipping of outbound

akhil-mac@Akhils-MacBook-Air dingo % go run ./cmd/dingo/ --dev-mode=true
{"time":"2025-07-27T20:51:39.302991-05:00","level":"INFO","msg":"maxprocs: Leaving GOMAXPROCS=8: CPU quota undefined","component":"dingo"}
{"time":"2025-07-27T20:51:39.303101-05:00","level":"INFO","msg":"version: devel (commit )","component":"dingo"}
{"time":"2025-07-27T20:51:39.305366-05:00","level":"INFO","msg":"serving prometheus metrics on 0.0.0.0:12798","component":"node"}
{"time":"2025-07-27T20:51:39.660035-05:00","level":"INFO","msg":"listening for ouroboros node-to-node connections on 0.0.0.0:3001","component":"connmanager"}
{"time":"2025-07-27T20:51:39.660066-05:00","level":"INFO","msg":"listening for ouroboros node-to-client connections on 127.0.0.1:3002","component":"connmanager"}
{"time":"2025-07-27T20:51:39.660152-05:00","level":"INFO","msg":"listening for ouroboros node-to-client connections on dingo.socket","component":"connmanager"}
{"time":"2025-07-27T20:51:39.660174-05:00","level":"INFO","msg":"dev mode enabled, skipping outbound connections","component":"peergov","role":"client"}
{"time":"2025-07-27T20:51:39.660614-05:00","level":"INFO","msg":"starting gRPC listener on 0.0.0.0:9090","component":"utxorpc"}

2. Passed devMode value through a config file like devMode as true then it skips the outbound connections

akhil-mac@Akhils-MacBook-Air dingo % go run ./cmd/dingo/ --config test-dingo.yaml
{"time":"2025-07-27T20:52:09.976368-05:00","level":"INFO","msg":"maxprocs: Leaving GOMAXPROCS=8: CPU quota undefined","component":"dingo"}
{"time":"2025-07-27T20:52:09.976431-05:00","level":"INFO","msg":"version: devel (commit )","component":"dingo"}
{"time":"2025-07-27T20:52:09.982251-05:00","level":"INFO","msg":"serving prometheus metrics on 0.0.0.0:12798","component":"node"}
{"time":"2025-07-27T20:52:10.419287-05:00","level":"INFO","msg":"listening for ouroboros node-to-node connections on 0.0.0.0:3001","component":"connmanager"}
{"time":"2025-07-27T20:52:10.419318-05:00","level":"INFO","msg":"listening for ouroboros node-to-client connections on 127.0.0.1:3002","component":"connmanager"}
{"time":"2025-07-27T20:52:10.419526-05:00","level":"INFO","msg":"listening for ouroboros node-to-client connections on dingo.socket","component":"connmanager"}
{"time":"2025-07-27T20:52:10.419675-05:00","level":"INFO","msg":"dev mode enabled, skipping outbound connections","component":"peergov","role":"client"}
{"time":"2025-07-27T20:52:10.423003-05:00","level":"INFO","msg":"starting gRPC listener on 0.0.0.0:9091","component":"utxorpc"}

[agaffney]

We should use a temp directory for this test file. This avoids the possibility of accidentally overwriting/removing a file that already exists.

[arepala-uml]

Made the changes and please review it.