p4info2ddlog: accept more standard P4 syntax

[debnil]

Currently, a Nerpa programmer has to format various P4 entity names to be compatible with DDlog relations. This includes capitalizing P4 types and camel casing, rather than snake casing, table names.

We should write some utility functions so that p4info2ddlog can accept a fully standard-looking P4 program and correctly generate DDlog relations.

[mihaibudiu]

What are P4 relations?
This will cause problems similar to Windows filesystems which are not case sensitive.
So there will be some restrictions on the P4 programs that people can write.

[debnil]

Good catch. Edited P4 relations to "P4 entity names".

And I think that makes sense. I'll tag you in that PR for review.