Value for sonar.branch.target in release and master branches?

[abitmore]

Bug Description

There is a comment in sonar-project.properties:

# should be changed in hardfork branch and removed in release branches
sonar.branch.target=develop

Although I don't know what the parameter is and why the comment says so, it seems incorrect that we have that value in master branch. I think
1. when creating new release we need to update the value in master branch, and (update: 2 will obsolete 1)
2. ideally we should have a build helper script to update the value when building the project, so that we don't need to update it every time when creating a new branch, nor need to fix conflicts caused by it when merging branches.

Impacts
Describe which portion(s) of BitShares Core may be impacted by this bug. Please tick at least one box.

• API (the application programming interface)
• Build (the build process or something prior to compiled code)
• CLI (the command line wallet)
• Deployment (the deployment process after building such as Docker, Travis, etc.)
• DEX (the Decentralized EXchange, market engine, etc.)
• P2P (the peer-to-peer network for transaction/block propagation)
• Performance (system or user efficiency, etc.)
• Protocol (the blockchain logic, consensus, validation, etc.)
• Security (the security of system or user data, etc.)
• UX (the User Experience)
• Other (please add below)

CORE TEAM TASK LIST

• Evaluate / Prioritize Bug Report
• Refine User Stories / Requirements
• Define Test Cases
• Design / Develop Solution
• Perform QA/Testing
• Update Documentation

[abitmore]

Background: we introduced a change in #1750 that requires some actions when merging branches, but haven't documented it in Git Flow, so I guess nobody remembered it.

[abitmore]

There is a related build helper script in the project.

[abitmore]

Fixed by #2102.