Better custom Chrome path support in WSL

[yhatt]

When Marp CLI is running on WSL, currently it will always expect to use Chrome located on the host Windows. Using custom chrome path set by CHROME_PATH env is still work, but it may bring mismatch of path style for temporary files and directories between Windows and POSIX. For example, the profile directory for Puppetter will be created with Windows style path, when setting chrome path to Chrome hosted on Linux.

Determining which OS running on from detected Chrome path is better than the current logic. Especially WSL2 cannot use Windows Chrome for now, so user must rely to custom Chrome path setting.