#541 - Disable comments

[Abijeet]

Towards #541

Following has been done,

1. Added an option under app settings - Disable comments
2. If this is turned on then,
   1. Adding comments is disabled.
   2. Existing comments will not be shown.
   3. The entire comments section is removed and no message is shown stating that comments are disabled.

Two things are debatable here,

1. Do we show a message stating that comments are disabled? Not sure if it's needed, but can be easily added.
2. Do we show existing comments? I removed them to save an extra query to fetch the comments.

TODO

• Add test cases for this option.

[Abijeet]

@ssddanbrown - I'm done with this change, please take a look and let me know if there is anything you'd like me to change/tweak.

[ssddanbrown]

@Abijeet All looked great, I just renamed a variable but that's it. Thank you very much once again!