'SHOW SYSTEM' command: provide list of functions belonging to system packages

[pavel-zotov]

Packaged functions currently aren't shown in the output of SHOW SYSTEM (unlike packaged procedures).
It will be good if they also will be displayed there.
Currently system packages and their functions can be obtained using query:

select pg.rdb$package_name, 'packaged func', sf.rdb$function_name
from rdb$packages pg
left join rdb$functions sf on pg.rdb$package_name = sf.rdb$package_name
;

PKG_NAME            OBJ_TYPE       OBJ_NAME
==================  =============  ================
RDB$TIME_ZONE_UTIL  packaged func  DATABASE_VERSION
RDB$PROFILER        packaged func  START_SESSION
RDB$BLOB_UTIL       packaged func  IS_WRITABLE
RDB$BLOB_UTIL       packaged func  NEW_BLOB
RDB$BLOB_UTIL       packaged func  OPEN_BLOB
RDB$BLOB_UTIL       packaged func  SEEK
RDB$BLOB_UTIL       packaged func  READ_DATA

PS.
Ticked was created after discussion in #7411

[AlexPeshkoff]

Also unified display format for functions & procedures, made it a bit better readable when dealing with packages.

[pavel-zotov]

QA: test not needed. Issue is covered by functional/basic/isql/test_02.py and test_03.py