[topgen] Add support for instantiating uniquified ipgen IPs

[Razer6]

This PR adds basic support to render and instantiate uniquified IPs from ipgen. The change is done in the following way:

1. It is assumed that all ipgen IP templates support the module_instance_name parameter. This is not true for all IPs there. Though this parameter was added to all *.tpldesc files, even it is not used.
2. In topgen, when you instantiate an ipgen'ed (attr: "ipen"), you specify three different fields:
   1. template_type: This is the basic template type that is used to render the IP from.
   2. type: This is the uniquified type.
   3. name: This is the actual instance name used in the top-level SystemVerilog file.

Let's make an example: To render a uniquified rv_plic you would set the following parameters in the HJSON:

{
  template_type: "rv_plic"
  type:          "my_fancy_plic"
  name:          "my_plic_name"
  ...
}

This would render and create new module my_fancy_plic and the instantiation would look like:

my_fancy_plic #(
   ...
 ) u_my_plic_name (
   ...
 );

Note, currently, only the AC ranges, RACL Ctrl, and the PLIC support this kind of uniquification. The alert handler would support it in theory. However, here, the template needs a few modifications as the uniquication there does create wrong file names.

[a-will]

LGTM

[vogelpi]

LGTM

[vogelpi]

CHANGE AUTHORIZED: hw/top_earlgrey/data/top_earlgrey.hjson

This PR adds some now keys to the Earlgrey hjson but there is no RTL or functional impact of this. This is fine.

[rswarbrick]

A couple of notes about improvements that are probably worth doing, but they can be in a follow-up so shouldn't block this PR.

[rswarbrick]

CHANGE AUTHORIZED: hw/top_earlgrey/data/top_earlgrey.hjson

We gain some new keys in the hjson file, but these won't have any effect on the Earlgrey configuration.

[vogelpi]

Thanks for your reviews, I am merging this to unblock follow-up work but it would still be good if @Razer6 could address the points you've raised.