Add ktlint to improve linting of kotlin files

[ShivamPokhriyal]

Summary

Saw this PR dimagi/commcare-core#1064 and thought it might be a good idea to add ktlint.

https://github.com/pinterest/ktlint is an amazing kotlin linter library which provides a built-in formatter so that we don't have to fix those issues manually(Although I had to fix some of the existing issues manually 😅 see 3rd commit).
PR uses https://github.com/pinterest/ktlint/#-with-gradle to add ktlint to the project.

After this change, the danger-lint pr tool should most probably be able to comment these lint issues on the PR(will have to test). Or maybe the lint task would make the PR checks fail(also need to test this).
Regardless, we now have 2 gradle tasks:

• ./gradlew ktlint this returns all the lint issues in the kotlin files.
• ./gradlew ktlintFormat will fix those lint issues

PS: We should consider upgrading kotlin version. Current is 1.3.72

Feature Flag

Product Description

Safety Assurance

• If the PR is high risk, "High Risk" label is set
• I have confidence that this PR will not introduce a regression for the reasons below
• Do we need to enhance manual QA test coverage ? If yes, "QA Note" label is set correctly

Automated test coverage

Safety story

[damagatchi]

Can one of the admins verify this patch?

[ShivamPokhriyal]

If the PR is high risk, "High Risk" label is set
I have confidence that this PR will not introduce a regression for the reasons below
Do we need to enhance manual QA test coverage ? If yes, "QA Note" label is set correctly

FYI: I'm unfortunately not able to add labels to the PR.

[shubham1g5]

@damagatchi ok to test

[ShivamPokhriyal]

@damagatchi retest this please

[shubham1g5]

@damagatchi retest this please

[dimagimon]

	1 Warning
⚠️	This PR does not contain any JIRA issue keys in the PR title or commit messages (e.g. KEY-123)

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