setting writable folders in init-script

It is said, that these folders are handled already by composer.json, what is definitely true. But if I can't (or don't want to) call composer create-project command, I have to run post-create-project-cmd manually like `composer run-script post-create-project-cmd`. IMHO, it's consistent to make such preparations in init script.
no need to set writable folders for console
removed unnecessary lines regarding writable dirs
Remove empty ActiveField errors and fix bootstrap templates
Merge pull request #3235 from crtlib/patch-5

setting writable folders in init-script
Merge pull request #3285 from mikehaertl/master

Fix bootstrap templates