Rename Metrics to Monitors and move it second

"Metrics" promised numbers. The tab holds tracked services, tracked processes
and network interfaces - things being WATCHED and their current state, only
one of which is a measurement. Monitors is what the panels actually are, and
it matches the word the agent's own config already uses for them.

Moved to second, ahead of Software. What is being watched on this box is the
question asked right after "what is it", and well before its application
inventory - which is reference data somebody goes looking for deliberately.

Tab order is now Details, Monitors, Software, Activity.

Contract 0.29.0 keeps its number. It is unreleased, so the group vocabulary it
introduces is still being settled and nothing can yet depend on the old name.
Both the server and the client fall back to 'details' for a group they do not
recognise, so a site that deploys these halves out of step gets a misplaced
card rather than a missing one.

Scope: product

shopdb/core/api/pluginui.py

@@ -25,7 +25,7 @@ pluginui_bp = Blueprint('pluginui', __name__)
 #
 # 'details' is first and is the fallback: it holds what an asset IS, which is
 # what a panel declaring nothing almost always contributes.
-ASSET_PANEL_GROUPS = ('details', 'software', 'metrics', 'activity')
+ASSET_PANEL_GROUPS = ('details', 'monitors', 'software', 'activity')
 
 
 def _collect(hookname):

shopdb/plugins/base.py

@@ -371,7 +371,7 @@ class BasePlugin(ABC):
                                       # keys, rendered generically - see warranty)
             'position':   int,        # order among panels
             'group':      str,        # OPTIONAL. Which tab on the detail page:
-                                      # 'details' | 'software' | 'metrics'
+                                      # 'details' | 'monitors' | 'software'
                                       # | 'activity'. Omitted means 'details'.
         }
 
@@ -383,12 +383,13 @@ class BasePlugin(ABC):
         existing plugin working untouched: an unknown or absent group resolves
         to 'details', which is the tab that holds what an asset IS. Reach for
         another group only when the panel is the thing that tab exists for -
-        an inventory listing, live telemetry, or a history feed.
+        what is being watched on the box, an inventory listing, or a history
+        feed.
 
         There is deliberately no group for controls. A panel that acts on the
         machine belongs beside the state it acts on: tracked services read as
-        telemetry first and a Start/Stop second, so they live in 'metrics' with
-        the rest of what the endpoint reports. Splitting the buttons away from
+        state first and a Start/Stop second, so they live in 'monitors' with
+        the rest of what is being watched. Splitting the buttons away from
         the state they change made a tab that held one card and answered no
         question on its own.