Add `fast-runtime` Cargo Feature for Quick Test Runs (#4332)

* add fast-runtime feature for reduced session times

* make democracy periods fast on fast-runtime

* propagate fast-runtime feature through cargo.toml files

* add fast motion and term durations to Kusama

* Update runtime/westend/Cargo.toml

Co-authored-by: Kian Paimani <[email protected]>

* set session time to 2 minutes to avoid block production issues

* formatting

* update Substrate

* set democracy fast periods back to 1min

* set launch period and enactment period to 1 block in fast-runtime

* remove unnecessary westend period configs

* add prod_or_test macro to allow specifying prod, test and env values for parameter types

* move prod_or_test macro into common module and use it consistently

* rename macro to prod_or_fast

* cargo +nightly fmt

* bump impl_versions

* newline

Co-authored-by: Kian Paimani <[email protected]>

* add note that env variable is evaluated at compile time

* newline

Co-authored-by: Kian Paimani <[email protected]>

* newline

Co-authored-by: Kian Paimani <[email protected]>

* cargo fmt

* impl_version: 0

* impl_version: 0

* use prod_or_fast macro for LeasePeriod and LeaseOffset

* use prod_or_fast macro in WND and ROC constants

Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: Giles Cope <[email protected]>