add bookie expand or shrink directories operation guide

[hangc0276]

Motivation

Currently, BookKeeper website doesn't have any operation guide for shrink or expand journal/ledger directories.

Changes

Add the operation guide for shrink or expand journal/ledger directories.

[zymap]

Here has a mail about this: http://mail-archives.apache.org/mod_mbox/bookkeeper-dev/202111.mbox/browser

[Vanlightly]

Here has a mail about this: http://mail-archives.apache.org/mod_mbox/bookkeeper-dev/202111.mbox/browser

Considering that data loss is an outcome of this operation, I think that should be clearly communicated here. When this data loss is addressed in a future patch we can modify the docs.

[dlg99]

maybe it is better to recommend to NOT use the shrink/expand procedure at all and instead decomm the bookie/add it back with shrunk/expanded storage.

[StevenLuMT]

hi @hangc0276 I would like to know how the current PR is going.

[StevenLuMT]

fix old workflow,please see #3455 for detail