Update futures and tokio for browser light client (#673)

* Make availability-store compile for WASM

* Use --manifest-path instead

* Make validation work on wasm!

* Switch to Spawn trait

* Migrate validation to std futures

* Migrate network to std futures

* Final changes to validation

* Tidy up network

* Tidy up validation

* Switch branch

* Migrate service

* Get polkadot to compile via wasm!

* Add browser-demo

* Add initial browser file

* Add browser-demo

* Tidy

* Temp switch back to substrate/master

* tidy

* Fix wasm build

* Re-add release flag

* Switch to polkadot-master

* Revert cli tokio version to avoid libp2p panic

* Update tokio version

* Fix availability store tests

* Fix validation tests

* Remove futures01 from availability-store

* Fix network tests

* Small changes

* Fix collator

* Fix typo

* Revert removal of tokio_executor that causes tokio version mismatch panic

* Fix adder test parachain

* Revert "Revert removal of tokio_executor that causes tokio version mismatch panic"

This reverts commit cfeb50c01d8df5e209483406a711e64761b44ae9.

* Update availability-store/src/worker.rs

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Update network/src/lib.rs

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Update network/src/lib.rs

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Box pin changes

* Asyncify network functions

* Clean up browser validation worker error

* Fix av store test

* Nits

* Fix validation test

* Switch favicon

* Fix validation test again

* Revert "Asyncify network functions"

This reverts commit f20ae6548dc482cb1e75bc80641cfe55c6131a53.

* Add async blocks back in