Currently db will open when GetDBHandle method is invoked first time,
so GetDBHandle method needs to use mutex.
This patch makes db open and close in its lifecycle methods Start and
Stop, invokes Start only when peer starts and invokes Stop when peer
stops.
After that, methods in db do not need to support concurrency.

Change-Id: Id8612f2a846c5d626bd42c5cd4ae482076f6a975
Signed-off-by: grapebaba <281165273@qq.com>

Clarify process for adding and removing maintainers requiring
consensus agreement.

Change-Id: I5df4c5563fb9013468d20f9869b335c1b6faf973
Signed-off-by: Christopher Ferris <chrisfer@us.ibm.com>

Copied from commit sha 346f9fb448140e931fed73b46f528de6dacbc0d0
to Gerrit. Verified that all DCO signoff received or IBM
contribution.

Change-Id: I812a2f48382a3cd37e153cd056d0ea94b7f416a0
Signed-off-by: Christopher Ferris <chrisfer@us.ibm.com>