refactor: do_btree_posi_find() function
refactor: remove engine argument from do_btree_elem_get_by_posi function.
change 3 letter characters of bop gbp(get by position) operation stats.
new: bop pwg(position with get) command - draft version.
add bop pwg(position with get) unit testing.
refactor: bop gbp(get by position) unit testing.
refactor: remove JOON_BTREE_POSI_FIND_WITH_GET tag.
Add section link
Update section link
Add section links.
Update mistake.
Add section links
Handle efficiently too large offset value in bop get/mget.
Update command-btree-collection.md
Refactor: collection unit testing.
Configurable max collection size, but limitative.
Add bop pwg(position with get) description
Add a link to bop pwg section.
Merge branch 'master' into replication