refactor(dependency): Remove tree-kill dependency

[gcstarr]

Remove external tree-kill dependency and use only local tree-kill code

Closes #3156

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[x] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

What is the current behavior?

start action uses the abandoned tree-kill library while swc compiler code uses local tree-kill code.

Issue Number: 3156

What is the new behavior?

tree-kill dependency is removed. start action uses the local tree-kill code.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

tree-kill NPM package has some file descriptor related issues for some on MacOS due to issues with use of spawn command to create the shell process to build the process tree. Forks of this library, and the local tree-kill code, use execSync instead, which helps with this issue.