storage: do not add /boot among required partitions

In general it is recommended to have a separate /boot, but not strictly
required.

In some cases it is required but we need to add API for that, because it
depends mainly on the filesystem of the root partition.

So now the requirement regards mainly biosboot and efi partitions, which
is dependent on the platform.

pyanaconda/modules/storage/devicetree/viewer.py

@@ -484,6 +484,9 @@ def get_mount_point_constraints(self):
         This includes mount points required to boot (e.g. /boot/efi, /boot)
         and the / partition which is always considered to be required.
 
+        /boot is not required in general but can be required in some cases,
+        depending on the filesystem on the root partition (ie crypted root).
+
         :return: a list of mount points with its constraints
         """
 
@@ -499,7 +502,10 @@ def get_mount_point_constraints(self):
         for p in platform.partitions:
             if p.mountpoint:
                 constraint = self._get_mount_point_constraints_data(p)
-                constraint.required = True
+                if p.mountpoint == "/boot":
+                    constraint.recommended = True
+                else:
+                    constraint.required = True
                 constraints.append(constraint)
 
         return constraints