Add a new command 'yank-in-context'

Add a new command 'yank-in-context'

* lisp/simple.el (escaped-string-quote): New variable.
(yank-in-context): New command.
(yank-in-context--transform): Helper function.

* lisp/progmodes/sh-script.el (sh-mode): Set up an
escaped-string-quote function.
* lisp/progmodes/sql.el (sql-mode): Define escaped-string-quote.