erl_interface: Remove superfluous comma in enum erlang_char_encoding
[test_server] Remove unused code related to remote targets

After removing the functionality for remote target nodes in R16A,
there was still some unused code left and some documentation that was
not updated. This is now completed.
Fixed rekeying initiation and secured testcase
Merge branch 'sverk/erl_interface-trailing-enum-comma' into maint-r16

* sverk/erl_interface-trailing-enum-comma:
  erl_interface: Remove superfluous comma in enum erlang_char_encoding
Merge branch 'fredrik/ssh/fix-rekeying/OTP-10911' into maint-r16

* fredrik/ssh/fix-rekeying/OTP-10911:
  Fixed rekeying initiation and secured testcase
Prepare release
Fixed appup for 2.1.5
ssh: Test and enhance handling of nonexistent subsystem
ssh: Prepare for upcoming release

Note: If more things are added before the next releas the
appup will need more updates.
Merge branch 'sverk/erl_interface-trailing-enum-comma' into maint-r16

* sverk/erl_interface-trailing-enum-comma:
  erl_interface: Remove superfluous comma in enum erlang_char_encoding
Merge branch 'ia/ssh/errorhandling-nonexisting-subsystem/OTP-10714' into maint-r16

* ia/ssh/errorhandling-nonexisting-subsystem/OTP-10714:
  ssh: Prepare for upcoming release
  ssh: Test and enhance handling of nonexistent subsystem
  Prepare release
  Fixed rekeying initiation and secured testcase
Merge branch 'fredrik/ssh/fix-rekeying/OTP-10911' into maint-r16

* fredrik/ssh/fix-rekeying/OTP-10911:
  Fixed appup for 2.1.5

Conflicts:
	lib/ssh/src/ssh.appup.src
Merge branch 'siri/test_server/remove-unused-code/OTP-10607' into maint

* siri/test_server/remove-unused-code/OTP-10607:
  [test_server] Remove unused code related to remote targets
Update copyright notice
Merge branch 'maint-r16' into maint

Conflicts:
	lib/ssh/src/ssh.appup.src
	lib/ssh/test/ssh_sftp_SUITE.erl