Install boundary docs enhancements (#5261)

* adds install-boundary/install-clients page

* renames install-boundary/install to deploy, adds workflow notes

* renames install-boundary/deploy, adds redirect for install-boundary/install

* adds TOC for install-boundary section

* Apply suggestions from code review

Co-authored-by: Dan Heath <76443935+Dan-Heath@users.noreply.github.com>

* style fixes

* add next steps

* fixes TF configuration note

* use lowercase for Boundary installer

* removes beta warning and adds a note instead

* Apply suggestions from code review

Co-authored-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>

---------

Co-authored-by: Dan Heath <76443935+Dan-Heath@users.noreply.github.com>
Co-authored-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>

website/data/docs-nav-data.json

@@ -108,8 +108,8 @@
         ]
       },
       {
-        "title": "Install Boundary",
-        "path": "install-boundary/install"
+        "title": "Deploy Boundary",
+        "path": "install-boundary/deploy"
       },
       {
         "title": "Configure controllers",
@@ -123,6 +123,10 @@
         "title": "Initialize Boundary",
         "path": "install-boundary/initialize"
       },
+      {
+        "title": "Install Boundary clients",
+        "path": "install-boundary/install-clients"
+      },
       {
         "title": "Systemd install",
         "hidden": true,