1852: Improve ci r=mergify[bot] a=Diman0
## What type of PR?
Enhancement for CI.
## What does this PR do?
Moved logic for configuring the tag for images for testing branch (bors try) and building the images, from deploy.sh (deploy job) to the Build job. Now the images are only built once during the build job. This saves about ~10 minutes for the CI workflow for bors try. Now for all situations (bors try, bors r+ and merge with master) should take around 20 minutes.
I did not create yet another newsfragment since it is an internal enhancement.
### Related issue(s)
## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.
- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/guide.html#changelog) entry file.
Co-authored-by: Dimitri Huisman <diman@huisman.xyz>