Add command to display the stdout.txt data in terminal

[hkmatsumoto]

Link to the GCI Task:

• https://codein.withgoogle.com/dashboard/task-instances/5650967840686080/

Changes:

• Add a subcommand to show the content of stdout file of the specified submission, invoked by evalai submission SUBMISSION_ID stdout.
• Add a helper function of the subcommand.

CC: @yashdusing @RishabhJain2018 @pushkalkatara @Ram81 @vkartik97

[hkmatsumoto]

Being different from display_submission_result, I didn't add error handling codes for requests.exceptions.MissingSchema because they will not be called even if I add them.
See #248 for detail.

[Ram81]

@takitsuse can you share a screenshot of command output

[hkmatsumoto]

@Ram81
The content of stdout file:

The command output:

[pushkalkatara]

Looks good to me. @Ram81 let's approve this?

[yashdusing]

@takitsuse Should we add a failure test case in this PR as well ?
If not, then the PR LGTM

[hkmatsumoto]

@yashdusing I don't think we should add it as long as #248 isn't resolved and reachable error handling can't be added.

[hkmatsumoto]

Can I get an approval on this task then?

[pushkalkatara]

Let's approve this @yashdusing We can create a new GCI task with it if required.
Approved @takitsuse

[hkmatsumoto]

@Ram81 @pushkalkatara @yashdusing
It's embarrassing to say this but, it seems I misread the codes due to lack of experience about try-except clause. The error handling code was reachable in the first place.
I managed to add error handling code that is tested, closing #248.
Sorry for the confusion.

[krtkvrm]

@takitsuse
Can you also add the command to docs: evalai-cli/docs/index.html

[hkmatsumoto]

@vkartik97 Added 👍
By the way, I think I can implement a similar command for stderr file. Could you make a new GCI task for it if it is okay for you?