Fix multiple UnitTests

[dyfer]

Purpose and Motivation

This PR fixes a number of issues with UnitTests, particularly for running them in the CI:

• most (all?) tests using a server now use a unique server instance
  • the use of default server, particularly if it was not shut down, has led to multiple tests failing, some without reporting failure in the CI (i.e. with the Did not complete message)
  • TestFunction -test_plot arguably was hiding the server booting most covertly...
• a number of tests was fixed
• the link to the API quark, used by QPM for testing was updated to point to the address that's specified in the quarks directory
  • I'm not sure if this was causing any of the issues we experience in qpm or not...
• we now have 3483 3507 passing tests with no tests that did not finish
  • the number of tests mysteriously failing in CI has greatly dropped; it appears that most of these failures were due to issues with booting the server or using the default server
  • there's a handful of tests still excluded, I tried updating lists in Some tests have bugs #5359 and Some tests fail when run in CI #5360
• I've made some changes to qpm and pointed our CI at its new branch, most notably increasing overall test suite timeout from 10 to 20 minutes (macOS tests slightly exceed 10 minutes right now)

Types of changes

• Bug fix

To-do list

• Code is tested
• All tests are passing
• Updated documentation
• This PR is ready for review

[dyfer]

This PR is now ready for review :)

[dyfer]

TestServer_boot and TestServer_clientID* tests were effectively fixed in #5715, so I re-enabled them here.
Ready for further review :)

[joshpar]

Basically approved but want to consider the crucialfelix bit... otherwise, fine from my side to merge in

[joshpar]

I like this!