feat: Added Flank Wrapper

[piotradamczyk5]

Fixes #2041

This is the solution to have evergreen Flank. The wrapper will always use the latest version of Flank

Test Plan

How do we know the code works?

1. Build Flank wrapper with ./gradlew flank_wrapper:shadowJar
2. Run it with flankw/flankw.bat or java -jar flank_wrapper.jar and provide flank options as usual
3. Please notice that the latest version should be downloaded just once.

Checklist

• Documented
• Unit tested
• Flank wrapper created
• Flank wrapper release workflow prepared
• SHA-256 sum added to Flank

[mergify]

Title does not follow the guidelines of Conventional Commits.
Please adjust title before merge and use one of following prefix:

• build - Changes that affect the build system or external dependencies (dependencies update)
• ci - Changes to our CI configuration files and scripts (basically directory .github/workflows)
• docs - Documentation only changes
• feat - A new feature
• fix - A bug fix
• chore - Changes which does not touch the code (ex. manual update of release notes). It will not generate release notes changes
• refactor - A code change that contains refactor
• style - Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
• test - Adding missing tests or correcting existing tests and also changes for our test app
• perf - A code change that improves performance (I do not think we will use it)

[github-actions]

Timestamp: 2021-07-06 12:55:28
Buildscan url for ubuntu-workflow run 1004441355
https://gradle.com/s/fsnjce6zholwm

[bootstraponline]

This looks great! What do you think about using mixpanel to track # of downloads with the Flank wrapper? And use sentry to check to make sure any crashes are reported? These can be done in a follow up PR to keep this one small.

[piotradamczyk5]

This looks great! What do you think about using mixpanel to track # of downloads with the Flank wrapper? And use sentry to check to make sure any crashes are reported? These can be done in a follow up PR to keep this one small.

I will create a follow up tickets for it