WIP: Asciidoc (#407)

* Rename readme

* Add some Asciidoc demo

* Remove extra lines

api/README.adoc

+
+= Polkadot API
+
+placeholder
+//TODO Write content :)

cli/README.adoc

+
+= Polkadot CLI
+
+== Summary
+
+[source, toml]
+----
+include::Cargo.toml[lines=2..5]
+----
+
+include::doc/shell-completion.adoc[]

cli/doc/shell-completion.adoc

+
+== Shell completion
+
+The Polkadot cli command supports shell auto-completion. For this to work, you will need to run the completion script matching you build and system.
+
+Assuming you built a release version using `cargo build --release` and use `bash` run the following:
+
+[source, shell]
+source target/release/completion-scripts/polkadot.bash
+
+You can find completion scripts for:
+- bash
+- fish
+- zsh
+- elvish
+- powershell
+
+To make this change persistent, you can proceed as follow:
+
+.First install
+
+[source, shell]
+----
+COMPL_DIR=$HOME/.completion
+mkdir -p $COMPL_DIR
+cp -f target/release/completion-scripts/polkadot.bash $COMPL_DIR/
+echo "source $COMPL_DIR/polkadot.bash" >> $HOME/.bash_profile
+source $HOME/.bash_profile
+----
+
+.Update
+
+When you build a new version of Polkadot, the following will ensure you auto-completion script matches the current binary:
+
+[source, shell]
+----
+COMPL_DIR=$HOME/.completion
+mkdir -p $COMPL_DIR
+cp -f target/release/completion-scripts/polkadot.bash $COMPL_DIR/
+source $HOME/.bash_profile
+----

collator/README.adoc

+
+= Polkadot Collator
+
+placeholder
+//TODO Write content :)

consensus/README.adoc

+
+= Polkadot Consensus
+
+placeholder
+//TODO Write content :)

executor/README.adoc

+
+= Polkadot Executor
+
+placeholder
+//TODO Write content :)

network/README.adoc

+
+= Polkadot Network
+
+placeholder
+//TODO Write content :)

parachain/README.adoc

+
+= Polkadot Parachain
+
+placeholder
+//TODO Write content :)

primitives/README.adoc

+
+= Polkadot primitives
+
+placeholder
+//TODO Write content :)

runtime/README.adoc

+
+= Polkadot Runtime
+
+placeholder
+//TODO Write content :)

service/README.adoc

+
+= Polkadot Service
+
+placeholder
+//TODO Write content :)

src/README.adoc

+
+= Polkadot Src
+
+placeholder
+//TODO Write content :)

statement-table/README.adoc

+
+= Polkadot Statement table
+
+placeholder
+//TODO Write content :)

transaction-pool/README.adoc

+
+= Polkadot Transactin pool
+
+placeholder
+//TODO Write content :)