[docs] Move FIDL bindings docs to //docs

These documents will re-appear in the //docs repo.

Test: No behavior change
Change-Id: Id92e6ebd0459e731695a09d0778721df002b6c81

[fidl] Link to the fidl tutorial from the fidl docs entrypoint

Change-Id: I4557ae867b7a8160018bdd03f6e1abef7f6af5b0

[fidl][docs] Fix links.

Change-Id: Ie461bfa7950c3b717e79c170de1546c7914cf99b

[fidl][docs] Remove references to first-fit packing

This isn't implemented. If we do implement, we can re-add the
documentation.

Change-Id: Ia168b70086c8c0ad048d008e340ef95ccf7fc156

[fidl][docs] Clean up some formatting and language

Change-Id: Ie7f43a83232fd15baa639788a6deef55c9071d99

[fidl][docs] Refer to fidl as fidl, not fidl2

Change-Id: Id67dc99b0819388586bd43b0794474dfb908f0d5

[docs][fidl] Remove some cruft from fidl docs

While the implementation is in progress, the design more-or-less is
not.

Change-Id: If8cc17c99db63545b799d0d11a8337a018288bf1

[fidl][docs] Fix some links to the code

Change-Id: I7f33fc009951cb47793eac9bd52068bf1e64c8c3

[fidl][docs] Remove some dead things from the docs

Change-Id: I650642ac95ea5dcfa178f1e5a6f0afc6225651f8

[fidl][docs] Update docs to match the FIDL2 examples.

Change-Id: I09578c0728c12fcfeb65081390fb91862ae20d5e

[fidl][docs] 'package' was renamed to 'library', so fix the docs

Change-Id: Ibd8d8515bc2ca8f2a6de6c89e83481645529ef3e

[docs][fidl] Create FIDL markdown documents.

These were converted from google docs automatically, then fixed up
manually.

Note these may not be up to date. kulakowski@ will work on updating them
when he gets back from vacation.

TO-321

Change-Id: If974bcb00a46bfe605a1005287b7b31df717f427