Specialized ExpressionPattern classes

[mmatera]

This PR adds two ingredients to the Pattern refactor:

• Simple ordered pattern rules are now implemented by FixedBlankTupleExpressionPattern and SimpleOrderedExpressionPattern, which avoid dealing with the special code for handling orderless, flat, or oneidentity attributes.
• After loading all the Definitions, Deferred rules are resolved before starting the evaluations. With this, pattern matching is always done using the simplest pattern matching algorithm.

As motivation, this is the number of typical patterns created in the definitions object at load time:

Shape	Occurences	State
head[__]	746	✅ this round
head[_]	510	✅ this round
head[lit] (single literal atom)	275	already optimal (isliteral)
head[,]	260	✅ this round
head[___]	211	not implemented
head[]	85	alredy optimal (isliteral, vaccum)
head[,,_]	55	✅ this round
head[_,OptionsPattern]	47	more specific
head[_String]	45	typed
head[_List]	44	typed
head[_Integer]	29	typed

[rocky]

Where can I see benchmarks comparing with the existing code in master?

It would be interesting to see what improvements there are with the gs (Gries-Schneider) tests and with the Rubi package.