[flows] Various updates to tools and documents to suppose top/ip select

- The --flag=fsel_{fsel_opts} argument is added to various docs and hjsons

Signed-off-by: Timothy Chen <timothytim@google.com>

[flow] updates based on latest comments

Signed-off-by: Timothy Chen <timothytim@google.com>
diff --git a/hw/data/common_project_cfg.hjson b/hw/data/common_project_cfg.hjson
index 4558c72..824c4fe 100644
--- a/hw/data/common_project_cfg.hjson
+++ b/hw/data/common_project_cfg.hjson
@@ -33,4 +33,7 @@
       BRANCH=`git rev-parse --abbrev-ref HEAD`;                                                                  \
       echo "Revision: [\`$COMMIT_SHORT\`](https://github.com/lowrisc/opentitan/tree/$COMMIT_LONG) on \`$BRANCH\`";
       '''
+
+  // The current design level
+  design_level:  "ip"
 }