Merge #19464: net: remove -banscore configuration option

06059b0c2a net: rename DEFAULT_BANSCORE_THRESHOLD to DISCOURAGEMENT_THRESHOLD (Jon Atack)
1d4024bca8 net: remove -banscore configuration option (Jon Atack)

Pull request description:

  per https://github.com/bitcoin/bitcoin/pull/19219#issuecomment-652684340, https://github.com/bitcoin/bitcoin/pull/19219#discussion_r443074487 and https://github.com/bitcoin/bitcoin/pull/19219#issuecomment-652699592. Edit: now split into 3 straightforward PRs:
  - net: remove -banscore configuration option (this PR)
  - rpc: deprecate banscore field in getpeerinfo (#19469, *merged*)
  - gui: no longer display banscores (TBA in the gui repo)

ACKs for top commit:
  MarcoFalke:
    review ACK 06059b0c2a 📙
  vasild:
    ACK 06059b0c

Tree-SHA512: 03fad249986e0896697033fbb8ba2cbfaae7d7603b1fb2a38b3d41db697630d238623f4d732b9098c82af249ce5a1767dd432b7ca0fec10544e23d24fbd57c50

doc/release-notes.md

@@ -121,6 +121,11 @@ Build System
 Updated settings
 ----------------
 
+- The `-banscore` configuration option, which modified the default threshold for
+  disconnecting and discouraging misbehaving peers, has been removed as part of
+  changes in this release to the handling of misbehaving peers. Refer to the
+  section, "Changes regarding misbehaving peers", for details. (#19464)
+
 - The `-debug=db` logging category, which was deprecated in 0.20 and replaced by
   `-debug=walletdb` to distinguish it from `coindb`, has been removed. (#19202)