Re-activate `import --debug` support
Add time estimate to CLI output
Initial migration of insight to slf4j

The individual configuration files will need
to be translated via the logback tools for this
to be completed.
Configure CLI to use etc/logback-cli.xml
Add newline to logback-cli.xml pattern
Add `--checksum_algorithm` from the CLI

Especially when using symlinks, there's no need to use a heavy
checksum. This may not be the ideal situation, i.e. requiring the
user to choose. Perhaps the `FileTransfer` API could suggest an
algorithm.
Add `--minutes-wait` option to CLI

Similar to `--wait` for `bin/omero chgrp` and friends,
setting `--minutes-wait` for the import process disconnects
once the files have been transfered. "Disconnectin from..."
is printed to the CLI and the process exits. Currently, the
`ImportProcessPrx` is left open on the server and must be
manually closed.
Improve name of servants

Import processes returned from:

```
  bin/omero shell --login
  client.getStatefulServices()
```

previously had very opaque (UUID-based) names.
This commit adds a readable string to them.
Add `--close_completed` advanced option to the CLI

To re-claim resources left open with `--minutes_wait`,
the new `--close_completed` option checks for any process
**in the current session** and closes it.

```
$ bin/omero import -- --minutes_wait=0 ...
... Disconnecting from import process...

$ bin/omero import -- --close_completed
Done: f318cbda-d91d-4123-bef4-467e5c4393e4/e7c27250-ac59-4337-bb0f-efd6fdb47fbd-ManagedImportProcessI
1 service(s) processed
```

For closing in other sessions, it will be necessary to first
find the sessions and join them.
Fix longopt number for `--transfer`
Remove short-form `-t` for transfers
Switch Insight to slf4j.
Add missing log file entry.

Entry got removed by mistake.
Fix logback pattern as x flag (NDC) is unsupported.
Update some commented-out log4j with slf4j.
Make LOGDIR configurable for Python processes (See #11943)

Java processes are being explicitly given the OMERO_LOGFILE
variable. Python processes make use of omero.util.LOG_DIR for
choosing a location. Now this is configurable via
`omero.logging.directory`.
Add pointer to master.{out,err} config (See #11943)

The node logging configuration does not make use of the
`${OMERO_*}` variables. Instead, these must be set manually
in the etc/*.cfg files.
Remove unused log4j-cli.properties file.
Change logging in import-cli
Add `--wait_completed`

After multiple imports, it's now possible to wait for all of them
to complete in a single operation. A while loop is started which
continues until no import processes are found.