* Promote ChiselEnum user APIs from experimental (#2929)

They are commonly used and if we were ever to change them, we will need
to go through a deprecation process anyway.

Note that the EnumAnnotations remain in chisel3.experimental because,
like all Chisel annotation support, they are slated to be deprecated and
removed.

(cherry picked from commit 424e9446f1675fe0168e22bdfbbe85db997376e6)

# Conflicts:
#	docs/src/cookbooks/verilog-vs-chisel.md
#	docs/src/explanations/chisel-enum.md

* Maintain binary compatbility, use aliases in chisel3 package

* Deprecate the actual classes in chisel3.experimental
* Also fix backport conflicts

Co-authored-by: Jack Koenig <koenig@sifive.com>

(cherry picked from commit b91a2050aeb143aa80762dfb1b40f1e5035de4b5)

Co-authored-by: Megan Wachs <megan@sifive.com>

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
(cherry picked from commit fce8394bb0ddc9ae0d9c6668e034e483bd6b71c5)

Co-authored-by: Jack Koenig <koenig@sifive.com>

Co-authored-by: Megan Wachs <megan@sifive.com>
(cherry picked from commit 26100a875c69bf56f7442fac82ca9c74ad3596eb)

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Add PartialDataView.supertype (#2826)

This factory method makes it easy to create PartialDataViews from a
Bundle type to its supertype. Because of the typing relationship, there
is no need to provide a mapping between fields. The only thing necessary
is to provide a function for constructing an instance of the supertype
from an instance of the subtype.

(cherry picked from commit 251d454a224e5a961438ba0ea41134d7da7a5992)

# Conflicts:
#	core/src/main/scala/chisel3/experimental/dataview/package.scala
#	src/test/scala/chiselTests/experimental/DataView.scala

* Resolve backport conflicts

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Add unit test for Issue 2760

* checkpoint: Fix for nested instance

* remove comments about stuff not working

* make the test check the output a little more

* relax the requirement on returning empty ioMap

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

* Update core/src/main/scala/chisel3/Data.scala

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Update src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

* Add another unit test which unfortunately still passes

* Update core/src/main/scala/chisel3/Data.scala

* Update src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
(cherry picked from commit 1f9f26dc2bffcb4cc4daf2dc16c5cb455c6769ef)

Co-authored-by: Megan Wachs <megan@sifive.com>

(cherry picked from commit 7fa0d8bf1cafcdf141046476a100abf021bdcac4)

Co-authored-by: Zachary Yedidia <zyedidia@gmail.com>

Used for separate elaboration of Definition and Instance

(cherry picked from commit 48d57cc8db6f38fdf0e23b7dce36caa404c871b8)

Co-authored-by: Girish Pai <girish.pai@sifive.com>

(cherry picked from commit 77a6c93592d5766d66f199720fc6d69478005091)

Co-authored-by: Jack Koenig <koenig@sifive.com>