* hasse/remove_old_IO_requests/OTP-15695:
  stdlib: Remove old I/O-requests from test suites
  stdlib (doc): Do not mention old requests
  snmp: Update old format I/O-request
  sasl: Use encoding when reading terms
  parsetools (doc): Update old format I/O-requests
  mnesia: Update old format I/O-request
  kernel: Update old format I/O-requests
  stdlib: Remove no longer used function
  kernel: Remove commented out code
  stdlib: Remove commented out code

* maint:
  Correct dump_log_write_threshold default value

Correct documentation on dump_log_write_threshold default value

* maint:
  mnesia: Bump protocol version
  mnesia: Introduce sync_asym_trans protocol
  observer: Fixes for html viewers
  observer: Support darkmode gui

* dgud/mnesia/sticky-bug/ERL-768/OTP-15979:
  mnesia: Bump protocol version
  mnesia: Introduce sync_asym_trans protocol

* maint:
  mnesia: Fix deadlock caused by add_table_copy

```erl
1> mnesia:system_info(dump_log_time_threshold).
1000
```

Looks like a missing `0`!

Remove unsupported conversions from the old protocols.
This means mnesia on OTP-R18 nodes is no longer able to connect to
OTP-22 mnesia nodes.

Add protocol conversion for old nodes and sync_asym_trans transactions.

Transactions with sticky locks could with async_asym transactions be
committed in the wrong order, since asym transaction are spawned on
the remote nodes.

See ERL-768.