add Tech Preview watermark to docs

Signed-off-by: Karl W. Schulz <karl.schulz@amd.com>

src/docs/conf.py

@@ -50,10 +50,12 @@ install("sphinx_rtd_theme")
 extensions = [
     "sphinx.ext.githubpages",
     "myst_parser",
+    "sphinxmark",
 ]
 
 show_authors = True
 
+
 myst_heading_anchors = 4
 # enable replacement of (tm) & friends
 myst_enable_extensions = ["replacements", "dollarmath"]
@@ -70,6 +72,17 @@ source_suffix = {
     ".md": "markdown",
 }
 
+sphinxmark_enable = True
+sphinxmark_image = 'text'
+sphinxmark_text = 'Tech Preview'
+sphinxmark_text_size = 80
+sphinxmark_div = 'document'
+sphinxmark_fixed = False
+sphinxmark_text_rotation = 30
+sphinxmark_text_color = (128,128,128)
+sphinxmark_text_spacing = 800
+sphinxmark_text_opacity = 30
+
 from recommonmark.parser import CommonMarkParser
 
 source_parsers = {".md": CommonMarkParser}