Deploy assignment: set the default Custom_Max_Papers from the configuration max_papers value

[melisabok]

When PCs want to reassign reviewers after the assignment are deployed, they want to use the checkbox in the edge browser to filter out reviewers who reached the quota. Most of the reviewers don't a have a specific quota so we need to use the default one that is never set.

I propose to set this value when the assignments are deployed and read the value from the configuration note max_papers. cc @celestemartinez