PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/NativeScript/blob/master/DevelopmentWorkflow.md#running-unit-tests.
• Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/WritingUnitTests.md.

This pull request:

• installs tns-core-modules and tns-platform-declarations packages from source
• updates tsconfig.json files
• updates webpack.config.json files
• adds mochawesome-report folder to repo's root .gitignore file and delete unnecessary .gitignore files
• delete unnecessary README.md files
• delete unnecessary nsconfig.json files

... to tests and e2e applications.