Wait for tuskar-api to start up

tuskar-ui runs immediately after tuskar-api. There is a chance
that the api has not come up completely before 101-tuskar-ui runs.
This patch adds a five second wait if tuskar-api is found to be
not running.

Change-Id: I5c9ff917d7f24b704e17d336cc1f79d211abd0a9
Closes-Bug: 1394430
reset-db to get all db parameters from the config

Refactor elements/boot-stack/bin/reset-db introducing a convenience
function to extract database name, user and password from the .db
configuration parameter and use those values to pass to os-db-create.

Includes an optional default dsn with a common db-password parameter,
and will forego the db create if neither the .db configuration nor
the default are provided.

Intent is to facilitate service level control on db passwords.

Change-Id: I6e109ce93e4c074dcb5fdfb0749799c869c25dd6
Merge "Wait for tuskar-api to start up"
Merge "reset-db to get all db parameters from the config"