gitignore: Cleanup boilerplate, sort
gitignore: Cleanup boilerplate, sort

`/lib` and `/share` being listed in gitignore means that
every time someone tries to commit `isso/js/app/lib` or
`share/isso.conf`, git will throw a confusing warning.

Also sort some duplicate entries and move entries inside
blocks where they make more sense.

posativ/isso,posativ/isso,posativ/isso,posativ/isso