Fixes #15: config2vmess: Parsing the correct address and port from config files

[AliSawari]

Fixes #15, #13

the command config2vmess was previously reading the address and port from the tag property in the outbound item object, which was resulting into the error mentioned in the linked issue. it is now parsing the correct data from the vnext item object, which contains the actual data for the address and port.

Additionaly this PR also included an example config.json for a correct vmess config file for testing purposes. located in config-examples folder

Changes:

• parse correct address and port from config file
• added null check operator for object props (obj?.prop) to remove the cannot read prop of undefined errors
• added new vmess config.json for a correct example
• added pnpm-lock.json to gitignore, because there's an already existing lock file for npm.