* PoC

* introduce IdProvider trait

* revert Cow stuff

* Update ws-server/src/server.rs

* fix tests

* cargo fmt

* use 'static lifetime in SubscriptionId

* fix tests

* fmt

* make tests compile again

* fix tests

* Fix tests

* Move IdProvider impls to own module

* move `sub-id gen` types to `core`

* fix doc links

* make rand non-optional dep

* feature gate: id provider

Co-authored-by: David Palm <[email protected]>

* extract ws client to async client

* bring back jsonrpsee-ws-client crate

* new crate core client

* add missing file

* jsonrpsee crate: add core client

* rexport core client

* more re-exports

* downgrade trait bounds

* update version

* fix nits

* send close reason

* Update types/src/traits.rs

* move 'TEN_MB_CONST' to core

* Update client/core-client/Cargo.toml

Co-authored-by: David <[email protected]>

* Update client/core-client/src/lib.rs

Co-authored-by: David <[email protected]>

* cargo fmt

* Update client/ws-client/src/lib.rs

Co-authored-by: David <[email protected]>

* Update client/ws-client/src/lib.rs

Co-authored-by: David <[email protected]>

* move `async-client` core

The `async-client` is hidden behind a new feature flag `async-client`
because it brings in additional dependecies such as tokio rt.

* fix docs

* add example how to use "core client"

* fix build

* Update http-server/Cargo.toml

* Update client/transport/Cargo.toml

Co-authored-by: David <[email protected]>