Fix:2964 obtain Postgres DB URL from ENV using branches get command

[yaten2302]

What kind of change does this PR introduce?

This PR introduces a new feature to enable users to obtain the Postgres db url from the .env using the branches get command.

What is the current behavior?

Fixes #2964

What is the new behavior?

This PR adds a new flag to the branches get command to help users to get the postgres db url from the env.

Additional context

Add any other context or screenshots.

[yaten2302]

@sweatybridge , I've a doubt, that as you mentioned in this comment, that a new --output flag should be added to the branches get command. But, while implementing that, it's showing an error that the output flag is being redeclared. So, is it possible that instead of using the output flag, we can use a Boolean var postgres-url?

Also, as you mentioned, that the postgres_url and prostgres_url_non_pooling has to be added if this flag is mentioned with the command and the code can be reused from the bootstrap command. But, while I was checking the writeDotEnv func, it writes the complete thing to the .env file. But, I'm confused that how can I get the postgres_db_url from the writeDotEnv func? Because, I was having some issues in adding the postgres_db_url to the resp, could you guide that how can I add the same to the resp, so that it can be used to display it on the output table for the user.