Closes#61145.
This PR adds a quota-aware filesystem plugin to Elasticsearch. This plugin
offers a way to provide user quota limits (specifically, total quota size
and available quota size) to Elasticsearch, in an implementation-agnostic
manner.
As part of this work, this PR also introduces the concept of "bootstrap
only" plugins, which are excluded from the normal plugin loading process.
Finally, note that this implementation supports `createLink(...)`, since ES
/ Lucene use hard links where possible.
Rory Hunter