utils: move olib to contrib directory

Affects-bug: lp-1218833
gnetlist: simplify processing of include blocks in spice-sdb

Taking into account the 'value' attributes in addition to the 'file'
attributes only in combination with the 'embedd_mode' flag (only for
embedding of files) adds unnecessary complexity and ambiguity to the
backend.

Closes-bug: lp-1258843
gnetlist: fix spice-sdb crash when opened file doesn't exist
symbols: removed two not more functional scripts

These scripts have not been working since the sch/sym format
change and update of the VHDL symbols with gsymupdate in 2003 (in
the commit 7b142bcdcff026e6726d23474533eb4f130f07e5).

Affects-bug: lp-1216798
symbols: removed mistaken attribute from VHDL symbols

The attribute VERILOG_PORTS has been mistakenly added some time ago
because of an error in the converting script (deleted in the previous
commit).

Affects-bug: lp-1216798
symbols: changed attribute visibility for some VHDL symbols

Discussed in the geda-user mailing list.
The visibility of some attributes considered to be confused to some
users (e.g. input port has visible pintype=OUT attribute, which is
right in itself since the attribute is used for the gnetlist DRC
backend).

Affects-bug: lp-1216798
symbols: fix refdes placement for a VHDL symbol

Closes-bug: lp-1216798