correct path to module
platform: path manager update

- config directory checked/created on startup (instead of every call)
- config directory created only if startup is possible
- forced home path verification added
- helper method introduced to facilitate use of platform-specific dirs
- constants and method groups arranged
- cleanup (typos, annotations, dead code)
Cleanup (system dir write-ability is checked earlier)
IDEA-114283 (diagnostic)
Minor optimization (empty map creation avoided)