[Plasma] Support setting memory quotas per plasma client for better isolation

[asfimport]

Currently, plasma evicts objects according a global LRU queue. In Ray, this often causes memory-intensive workloads to fail unpredictably, since a client that creates objects at a high rate can evict objects created by clients at lower rates. This is despite the fact that the true working set of both clients may be quite small.

cc @pcmoritz

Reporter: Eric Liang / @ericl
Assignee: Eric Liang / @ericl

PRs and other links:

• GitHub Pull Request #4885

_{Note: This issue was originally created as ARROW-5955. Please see the migration documentation for further details.}

[asfimport]

Philipp Moritz / @pcmoritz:
Issue resolved by pull request 4885
#4885