doc: reorganize documentation

We've been expanding documentation, and now need to organize things a bit
cleaner and separate content into new major folders: Introduction, Getting
Started, User Guides, Developer Guides, Tutorials, and Release notes..

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>

doc/user-guides/acrn-shell.rst

@@ -0,0 +1,55 @@
+.. acrnshell:
+
+ACRN Shell Commands
+###################
+
+The ACRN hypervisor shell supports the following commands:
+
+.. list-table::
+   :header-rows: 1
+   :widths: 40 60
+
+   * - Command (and parameters)
+     - Description
+   * - help
+     - Displays information about supported hypervisor shell commands
+   * - vm_list
+     - Lists all VMs, displaying VM Name, VM ID, and VM State (ON=running)
+   * - vcpu_list
+     - Lists all VCPUs in all VMs
+   * - vcpu_pause <vm_id, vcpu_id>
+     - Pauses a specific VCPU
+   * - vcpu_resume <vm_id, vcpu_id>
+     - Resumes a specific VCPU
+   * - vcpu_dumpreg <vm_id, vcpu_id>
+     - Dumps registers for a specific VCPU
+   * - vcpu_dumpmem <vm_id, vcpu_id, GVA, length>
+     - Dumps memory for a specific VCPU, starting a given address, and for
+       a given length (in bytes)
+   * - vm_console
+     - Switches to the SOS's console
+   * - int
+     - Lists interrupt information per CPU
+   * - pt
+     - Shows pass-through device information
+   * - reboot
+     - Triggers a system warm reboot (immediately)
+   * - lsreq
+     - Shows ioreq information
+   * - dump_ioapic
+     - Shows native ioapic information
+   * - vmexit
+     - Shows vmexit profiling
+   * - logdump <pcpu_id>
+     - Dumps the log buffer for the physical CPU
+   * - trace <cpumask, ms>
+     - Dumps a CPU's recent events within <ms> milliseconds
+   * - get_loglevel
+     - Get the loglevel
+   * - set_loglevel <console_loglevel> [mem_loglevel]
+     - Set loglevel [0 (none) - 6 (verbose)] for the console and optionally
+       for memory
+   * - cpuid <leaf> [subleaf]
+     - Displays the CPUID leaf [subleaf], in hexadecimal
+   * - crash
+     - Triggers a system crash

doc/user-guides/index.rst

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+.. _userguides:
+
+User Guides
+###########
+
+.. toctree::
+   :maxdepth: 2
+
+   acrn-shell.rst
+   tools.rst

doc/user-guides/tools.rst

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+.. _tools:
+
+Tools
+#####
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   ../tools/**