Change gds naming conventions

[pvnbhargava]

Currently GDS's are named with the concatenation of the gds_filename and impl_lib parameters from the spec file. Change this to only use the gds_filename.

[sbuchbinder]

I am going to reopen this issue. I think we need to figure this out again in light of the refactor.
In db, there are lib_name and impl_cell uses that I am confused by.

[pvnbhargava]

Yes, before now since gds generation was tied together with OA generation, TemplateDB utilized the impl_lib variable to name the gds. However, with the new separation of plugins, it's a good idea to change this up.

[sbuchbinder]

BigRefactor actually messes this up a bit because it uses the gds_plugin.export_content_list to export the design, which names the file based on the base gds_filepath and new property of gds_plugin called self.lib_name.
This means that the gds, flat gds, dataprep, and lsf gds-s are all named the same.

For now, I will hack together a solution where you pass an argument specifying how you want to append to the name...

[sbuchbinder]

We will also need to fix naming of the lsf exporter

[sbuchbinder]

in layout_manager, for impl_lib and impl_cell, to be compatible with bag:
check if they exist. if so use them, if not use project_name.
This allows us to remove impl_lib and impl_cell from the spec file.