Fix temp file cleanup and reorganized temp dir structure

[cmaglie]

Please check if the PR fulfills these requirements

• [X] The PR has no duplicates (please search among the Pull Requests before creating one)
• [X] The PR follows our contributing guidelines
• [X] Tests for the changes have been added (for bug fixes / features)

What kind of change does this PR introduce?

• Fix the cleanup of temporary files created during language server execution.
• All temporary files are now created under the same sub-directory of tmp

What is the current behavior?

• Some temporary files are not cleaned up correctly, see #145
• Temporary files are spread among TMP dir

  Language server temp directory:    C:\Users\cmagl\AppData\Local\Temp\system-includes-0f3fe3.clangd
  Language server build path:        C:\Users\cmagl\AppData\Local\Temp\arduino-language-server3185134839
  Language server build sketch root: C:\Users\cmagl\AppData\Local\Temp\arduino-language-server3185134839\sketch
  Language server FULL build path:   C:\Users\cmagl\AppData\Local\Temp\arduino-language-server795682186

What is the new behavior?

• All temporary files are removed on exit.
• All temporary files are created under the same subdir of TMP

  Language server temp directory:    C:\Users\cmagl\AppData\Local\Temp\arduino-language-server2854144105\system-includes-0f3fe3.clangd
  Language server build path:        C:\Users\cmagl\AppData\Local\Temp\arduino-language-server2854144105\build
  Language server build sketch root: C:\Users\cmagl\AppData\Local\Temp\arduino-language-server2854144105\build\sketch
  Language server FULL build path:   C:\Users\cmagl\AppData\Local\Temp\arduino-language-server2854144105\fullbuild

  Other information: Fix #145

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