Revert "Pin jquery.select2 to 3.3.1"

This reverts commit 9dad368d91afee0ff7bb9699af87771db1474346.
Revert "Enable IE8 width hack"

This reverts commit 8efb35f588ad5e1b8fc12632bce4be86b92b8a78.
Revert "Use "resolve" option for width calculation"

This reverts commit ee7277b2df420bde911da46c13aa22a5a4367d73.
Revert "Let the select2 element's be in inherited from the width of the source element"

This reverts commit 1ade1c915997a404be9dba4f778a8c76d255c60b.