NewContainment will replace Containment later in this commit chain, but
for now it is not yet being used.
NewContainment will allow a node to be contained for multiple pending
reverify jobs at a time. It is implemented by way of the reverify queue.
Refs: https://github.com/storj/storj/issues/5231
Change-Id: I126eda0b3dfc4710a88fe4a5f41780618ec19101
