Slim down repository config on https://scala-ci.typesafe.com/artifactory/

[SethTisue]

In the interest of hopefully speeding up the community build, I removed a bunch of probably-unused remote repositories from https://scala-ci.typesafe.com/artifactory/webapp/#/admin/repositories/remote , and also some repositories which had an includesPattern of **/*, I made more specific.

I based the changes on the local Artifactory config I've been using for local community build runs for ages, so I'm pretty sure the community build won't be affected (or if it is, I'll be able to resolve it quickly, ha ha ha "resolve").

But I don't know who all else might be using the scala-ci artifactory; perhaps some of the removed repositories were actually needed. If you are using it and you start getting resolution failures, let me know and we can work on either fixing the regression or finding another solution. (This Artifactory isn't intended for general use.)

[SethTisue]

I fixed a few regressions already, and all 3 community builds (2.11, 2.12, 2.13) now extract fully and are chugging along, so that's a good sign.

scala-runners was briefly unable to retrieve Scala nightly & PR snapshot builds — now fixed.

[SethTisue]

A few community build projects are failing (playframework, sttp) — I expect to straighten that out today.

[SethTisue]

note that there is some background/history at scala/community-build#408

[SethTisue]

some breakage downstream at scala/community-build#1216, gory details on that ticket