builds should collect warnings/deprecations

[tobybellwood]

As we deprecate functionality in the lagoon.yml (and elsewhere), there should be a mechanism for builds to be able to alert the users - firstly via the build logs, but also to be able to save a deployment as "completed with errors" or similar - these could then be passed to the UI

Some example deprecations were raised in:
uselagoon/lagoon#3136
uselagoon/lagoon-linter#21
uselagoon/lagoon-linter#22
uselagoon/lagoon-linter#23

[smlx]

The lagoon-linter has a deprecated profile for this purpose. See uselagoon/lagoon-linter#14 (comment)

[shreddedbacon]

#255 introduced warnings support, not sure if this closes this issue though, but could be used to identify other things to warn about?