Lift dependencies to the workspace (Part 1) (#2070)

Changes (partial https://github.com/paritytech/polkadot-sdk/issues/994):
- Set log to `0.4.20` everywhere
- Lift `log` to the workspace

Starting with a simpler one after seeing
https://github.com/paritytech/polkadot-sdk/pull/2065 from @jsdw.
This sets the `default-features` to `false` in the root and then
overwrites that in each create to its original value. This is necessary
since otherwise the `default` features are additive and its impossible
to disable them in the crate again once they are enabled in the
workspace.

I am using a tool to do this, so its mostly a test to see that it works
as expected.

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/client/offchain/Cargo.toml

@@ -42,7 +42,7 @@ sp-offchain = { path = "../../primitives/offchain" }
 sp-runtime = { path = "../../primitives/runtime" }
 sp-keystore = { path = "../../primitives/keystore" }
 sp-externalities = { path = "../../primitives/externalities" }
-log = "0.4.17"
+log = { workspace = true, default-features = true }
 
 [dev-dependencies]
 lazy_static = "1.4.0"