[manpages] Rewrite man pages in a simpler text format.

Makefile still needs work, but I wanted to commit to save progress.

man8/cache_dump.txt

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+NAME
+  cache_dump - dump cache metadata from device or file to standard output.
+
+SYNOPSIS
+  cache_dump [options] {device|file}
+
+DESCRIPTION
+  cache_dump dumps binary cache metadata created by the device-mapper cache
+  target on a device or file to standard output for analysis or postprocessing
+  in XML format.  XML formatted metadata can be fed into cache_restore in order
+  to put it back onto a metadata device (to process by the device-mapper
+  target), or file.
+
+  This tool cannot be run on live metadata.
+
+OPTIONS
+  -h, --help	Print help and exit.
+  -V, --version	Print version information and exit.
+  -r, --repair	Repair the metadata whilst dumping it.
+  -o {xml file>	Specify an output file for the xml, rather than printing to stdout.
+
+EXAMPLES
+  Dumps the cache metadata on logical volume /dev/vg/metadata to standard
+  output in XML format:
+
+    $ cache_dump /dev/vg/metadata
+
+  Dumps the cache metadata on logical volume /dev/vg/metadata whilst repairing
+  it to standard output in XML format: .sp
+
+    $ cache_dump --repair /dev/vg/metadata
+
+DIAGNOSTICS
+  cache_dump returns an exit code of 0 for success or 1 for error.
+
+SEE ALSO
+  cache_check(8), cache_repair(8), cache_restore(8)
+
+AUTHOR
+  Joe Thornber <ejt@redhat.com>, Heinz Mauelshagen <HeinzM@RedHat.com>
+