refactor parity-dapps-glue crate

[debris]

Currently parity-dapps-glue uses quasi, which is no longer maintained - serde-deprecated/quasi. Let's use refactor it to use proc-macro, syn and quote instead

cc @tomusdrw

[folsen]

Closing because UI is moving.

[sorpaas]

I think we probably still need to keep this issue open for a while. Currently parity-dapps-glue crate is still in the code -- we would either need to remove it or do the refactoring described in this issue.

[tomusdrw]

What is the glue still used for? As a workaround we can just hardcode the generated code instead of rewriting it.

[sorpaas]

@tomusdrw For our current code we're only using the WebApp trait and Info struct. They're perfectly fine to be moved to parity-dapps crate. The only issue is that if someone wants to create a new builtin dapp (https://github.com/paritytech/parity/tree/master/dapps/js-glue) in a customized version of parity, they rely on the js-glue crate right now.

No matter what we do, this will eventually be fixed when Parity UI takes over all dapps functionalities and we should then be able to remove the js-glue crate.

[folsen]

Ping @axelchalon this might be something semi-related to what you're working on and of interest for you to look at?

[axelchalon]

Hey, I don't think parity-dapps-glue is used for anything anymore. Built-in dapps are now completely handled by Parity UI.

I was thinking that as soon as the Parity UI network dapps PR is reviewed and merged, we can remove the whole dapps crate (incl. parity-dapps-glue) and dapps-related cli/config options in one fell swoop.

[axelchalon]

parity-dapps-glue removed in #9017