Accept cache as a parameter to constructor

[cmdcolin]

Our packages have stayed on old versions of quick-lru because updating to the latest causes bundling issues. jbrowse-web bundles at least three versions of quick-lru: v2, v4, and v6 (quick-lru v6 is vendored in @jbrowse/core/util/QuickLRU)

Two possible solutions are

accept quick-lru as parameter to constructor. this also gives maximum cache control to the application, which may have specialized needs

use quick-lru as a peerDependency, and still initialize it import it this library