Modularize Hammer CLI guide (theforeman#3251)

* Split configuring Hammer CLI
* Reorder sections in Hammer CLI guide
* Split off compared to sections
* Rename standalone Hammer CLI installation
* Rename troubleshooing with Hammer
* Fix order

guides/common/modules/con_hammer-authentication.adoc

@@ -0,0 +1,15 @@
+[id="hammer-authentication"]
+= Hammer authentication
+
+A {Project} user must prove their identity to {ProjectName} when entering hammer commands.
+Hammer commands can be run manually or automatically.
+In either case, hammer requires {Project} credentials for authentication.
+There are three methods of hammer authentication:
+
+* Hammer authentication session
+* Storing credentials in the hammer configuration file
+* Providing credentials with each hammer command
+
+The hammer configuration file method is recommended when running commands automatically.
+For example, running {Project} maintenance commands from a cron job.
+When running commands manually, {Team} recommends using the hammer authentication session and providing credentials with each command.

guides/common/modules/con_hammer-compared-to-project-api.adoc

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+[id="hammer-compared-to-{project-context}-api"]
+= Hammer compared to {Project} API
+
+For many tasks, both Hammer and {Project} API are equally applicable.
+Hammer can be used as a human friendly interface to {Project} API, for example to test responses to API calls before applying them in a script (use the `-d` option to inspect API calls issued by Hammer, for example `hammer -d organization list`).
+Changes in the API are automatically reflected in Hammer, while scripts using the API directly have to be updated manually.
+
+In the background, each Hammer command first establishes a binding to the API, then sends a request.
+This can have performance implications when executing a large number of Hammer commands in sequence.
+In contrast, a script communicating directly with the API establishes the binding only once.
+
+ifdef::satellite[]
+For more information, see the {APIDocURL}[_{APIDocTitle}_].
+endif::[]

guides/common/modules/con_hammer-compared-to-project-webui.adoc

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+[id="hammer-compared-to-{ProjectWebUI-context}"]
+= Hammer compared to {ProjectWebUI}
+
+Compared to navigating the {ProjectWebUI}, using Hammer can result in much faster interaction with the {ProjectServer}, as common shell features such as environment variables and aliases are at your disposal.
+You can also incorporate Hammer commands into reusable scripts for automating tasks of various complexity.
+Output from Hammer commands can be redirected to other tools, which allows for integration with your existing environment.
+You can issue Hammer commands directly on the base operating system running {ProjectName}.
+
+Access to base operating system on {ProjectServer} is required to issue Hammer commands, which can limit the number of potential users compared to the {ProjectWebUI}.
+Although the parity between Hammer and the {ProjectWebUI} is almost complete, the {ProjectWebUI} has development priority and can be ahead especially for newly introduced features.