Make all tests run and show summary table

[Bill-Becker]

This update to runtests.jl:

• Makes sure that all tests are run and displays a summary table at the end of the GitHub Actions step
  • By wrapping/nesting all the tests that we run on GitHub Actions within a high-level @testset, this gives a big summary table of all the nested @testsets after running all of them
  • Before, if there was certain errors in tests, the remaining tests would not run because it was not all nested under one
• Remove the "Imported Xpress tests" @testset now that we plan to only use HiGHS or other OS solver going forward, and all of those imported tests have been vetted and pass
• By including verbose=true, we see the results and a time of each testset even if they pass
• Removes an "inputs" @testset because there are tons of other inputs tests within other @testsets

There is still a bit of inconsistency for when we wrap certain @testsets within a higher-level @testset to categorize and group tests, so there's room to improve the organization of this for clarity. This PR does NOT attempt to take that on.

[adfarth]

Thanks for bringing back the summary table! Did you test this with having a test fail? (e.g. temporarily changing a test value)

[Bill-Becker]

Thanks for bringing back the summary table! Did you test this with having a test fail? (e.g. temporarily changing a test value)

@adfarth Yes because I had added these commits to another branch where I was developing something else, and I just cherry picked the commits into this branch off of develop. This branch had a couple of tests fail, with these same edits to runtests.jl:
https://github.com/NREL/REopt.jl/actions/runs/10363166826/job/28686315729