Add docs for testing module (#3984)

* overall stub + hersir and jormungandr automation

* added mjolnir/thor and loki readme's
added integration-tests.md
added automation.dm

* fmt

* Revert "Auxiliary commit to revert individual files from 4684c30"

This reverts commit ab5cc2dc8aac7cc1cd5a942ed900e1826166554c.

* review fixes + spelling fixes

doc/SUMMARY.md

@@ -42,3 +42,12 @@
 
 - [Specs](./specs/introduction.md)
   - [Network](./specs/network.md)
+
+- [Testing](./testing/introduction.md)
+  - [Jormungandr Automation](./testing/automation.md)
+  - [Hersir](./testing/hersir.md)
+  - [Thor](./testing/thor.md)
+  - [Mjolnir](./testing/mjolnir.md)
+  - [Loki](./testing/loki.md)
+  - [Integration tests](./testing/integration_tests.md)
+

doc/testing/automation.md

@@ -0,0 +1,54 @@
+# jormungandr-automation
+
+Incubator of all testing apis for the node and jcli:
+
+## build
+
+In order to build jormungandr-automation in main project folder run:
+```
+cd testing/jormungandr-automation
+cargo build
+```
+
+## jcli testing api
+
+Api that can be used to run jcli executable underneath and is capable to assert outcome of command. It can work with already installed jcli (using PATH variable) or custom path. For Example:
+
+```
+    let jcli: JCli = Default::default();
+    let private_key = jcli.key().generate("Ed25519Extended");
+    let public_key = jcli.key().convert_to_public_string(&private_key);
+```
+
+## jormungandr testing api
+
+Collection of automation modules for node interaction and configuration:
+
+* configuration - allows to configure node & blockchain settings,
+* explorer - explorer configuration/bootstrap & interaction module,
+* grpc - module for grpc internode connection library handling. capable of sending some RPC calls as well as bootstrap receiver instance,
+* legacy - module for loosely typed configuration. This allow to bootstrap older version of node, for example to satisfy need on cross-version testing,
+* rest - module for jormungandr REST api testing,
+* starter - module for bootstrapping node,
+* verifier - node state verifier
+* logger - api for jormungandr log handling/assertion
+* process - api for handling jormungandr process
+
+## testing
+
+Bunch of loosely coupled utility modules, mostly for additional configuration capabilities or benchmarking:
+
+* benchmark - measurements framework for various purposes, for example bootstrap time or how many transactions were successfully handled by node,
+* vit - additional helpers for voting capabilities,
+* asserts - asserts extensions, tailored for node needs,
+* block0 - block0 extensions, like easier access to blockchain setting or function to download block0,
+* collector - input collector utils,
+* configuration - test configuration helper (apps paths etc.),
+* keys - create default keys,
+* observer - simple observer framework,
+* panic - panic error reporting in test code,
+* process - process extensions,
+* resource - resources manager, mostly for tls certificates used for testing,
+* storage - node storage generators,
+* time - time utils, mostly for waiting for particular block date,
+* verify - substitute of asserts in case we don't want to panic eagerly when assertion is failed.