rhash: add page (#9973)

* rhash: add new command
---------
Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/common/rhash.md

@@ -0,0 +1,28 @@
+# rhash
+
+> Calculate or check common message digests.
+> More information: <https://rhash.sourceforge.net/manpage.php>.
+
+- Calculate default CRC32 digests of a file:
+
+`rhash {{path/to/file}}`
+
+- Recursively process a directory to generate an SFV file using SHA1:
+
+`rhash --sha1 --recursive {{path/to/folder}} > {{path/to/output.sfv}}`
+
+- Verify the integrity of files based on an SFV file:
+
+`rhash --check {{path/to/file.sfv}}`
+
+- Calculate the SHA3 digest of a text message:
+
+`rhash --sha3-256 --message '{{message}}'`
+
+- Calculate CRC32 digest of a file and output digest encoded in base64 using BSD format:
+
+`rhash --base64 --bsd {{path/to/file}}`
+
+- Use custom output template:
+
+`rhash --printf '{{%p\t%s\t%{mtime}\t%m\n}}' {{path/to/file}}`