[sqlite] Reflect DEFERRABLE and INITIALLY options for foreign keys

[sqlite] Reflect DEFERRABLE and INITIALLY options for foreign keys

Added support for the SQLite backend to reflect the "DEFERRABLE" and
"INITIALLY" keywords which may be present on a foreign key construct. Pull
request courtesy Michael Gorven.

Fixes: #8903
Closes: #8904
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/8904
Pull-request-sha: 52aa4cf77482c4051899e21bea75b9830e4c3efa

Change-Id: I713906db1a458d8f1be39625841ca3bbc03ec835
(cherry picked from commit 07760011b5176be03c7811e9a45933b473b8b80b)