[MRG] Proposed An App Icon

[huangyz0918]

Closes #117

What has been done to verify that this works as intended?

I added an icon, which looks like

Why is this the best possible solution? Were any other approaches considered?

N/A

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

N/A

Before submitting this PR, please make sure you have:

• [x] run ./gradlew checkCode and confirmed all checks still pass OR confirm CircleCI build passes
• [x] verified that any code or assets from external sources are properly credited in comments and/or in the about file.

[lakshyagupta21]

I think it would be great if you can start a thread over forum or slack channel, there are a lot of people who aren't active on Github or following github issues and PRs.

[huangyz0918]

@lakshyagupta21 Yeah, I just created a new thread in ODK forum, hope we can get more suggestions there!