Add support for PharArchiver tar file compression (tar.gz & tar.bz2)

Adds support for file extensions tar.gz and tar.bz2 where file
gets enabled compression is enabled if these are used.

Compression support is not added to zip file as Phar doc explicitly
says it is not supported on file level, and compression would then
have to be exposed differently as it uses same file name.

File size was in my limited testing reduced to 1/8th, but this depends on content, and probably machine/lib/php-version as well.

Todo (if approach is ok):
- update tests