Opcode renumbering (#209)

Many new opcodes have been added to the proposal since the last
opcode renumbering, and since we are in phase 3, the time is ripe
to finalize the opcode numbers for standardization. The goals of
this renumbering are:

 1. To maintain consistency with the ordering of MVP operations

 2. To organize sets of similar operations into tables such that the offset
 from an operation for one type to the same operation for the next
 type is constant for all operations in that set.

 3. To use round hexadecimal numbers for offsets where not too wasteful.

Co-authored-by: Deepti Gandluri <dtig@users.noreply.github.com>

Author: tlively