lava: add macros 'image_url()'

Macros for path calculation to the testing image for deploy.
It accepts only one string parameter -- file extension to be added
to the base image URL.

In case if global variable 'image_base_url' is set -- it is returned
with requested extension instead of on-the-fly calculation.

As a side effect -- it is possible to define the image for the test
via CLI without changing other variables, for instance:
  lqa -g lava/profiles.yaml -t image_base_url:'https://URL/name.img

'

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

lava/common-boot-macros.yaml

@@ -5,3 +5,11 @@
         zimage
     {%- endif %}
 {%- endmacro %}
+
+{% macro image_url(ext) -%}
+    {% if image_base_url is defined -%}
+        {{image_base_url}}.{{ext}}
+    {%- else -%}
+        {{baseurl}}/{{imgpath}}/{{image_date}}/{{arch}}/{{image_type}}/{{image_name}}.img.{{ext}}
+    {%- endif %}
+{%- endmacro %}

lava/common-boot-tpl.yaml

@@ -89,9 +89,9 @@ actions:
         prompts: ['copying time: [0-9ms\.\ ]+, copying speed [0-9\.]+ MiB\/sec']
       images:
         image:
-          url: {{baseurl}}/{{imgpath}}/{{image_date}}/{{arch}}/{{image_type}}/{{image_name}}.img.gz
+          url: {{boot.image_url('gz')}}
         bmap:
-          url: {{baseurl}}/{{imgpath}}/{{image_date}}/{{arch}}/{{image_type}}/{{image_name}}.img.bmap
+          url: {{boot.image_url('bmap')}}
       uniquify: false
       os: ubuntu
       writer:

lava/common-qemu-boot-tpl.yaml

+{% import 'common-boot-macros.yaml' as boot with context -%}
+
 device_type: {{device_type}}
 priority: medium
 
@@ -48,7 +50,7 @@ actions:
       images:
         rootfs:
           image_arg: -m 1024 -enable-kvm -cpu host -vga qxl -device virtio-rng-pci -drive if=pflash,format=raw,readonly,file=/usr/share/ovmf/OVMF.fd -drive if=virtio,format=raw,file={rootfs}
-          url: {{baseurl}}/{{imgpath}}/{{image_date}}/{{arch}}/{{image_type}}/{{image_name}}.img.gz
+          url: {{boot.image_url('gz')}}
           compression: gz
       os: ubuntu