Allow pillow customization.

[SimonFischer04]

Also allow to configure the used 'pillow' version. Like already implemented for 'esphome' (dashboard) version.

Preparation for concept in: #183

[SimonFischer04]

@DutchmanNL let copilot do this. Should work nicely, as there is already a good reference example.

(or / and add my second account ()https://github.com/SimonFischer042 as reviewer access to the repo as well - so can assign copilot and work directly here). For some kind of stupid reasons I can only use the copilot assignment there. PS: don't mention that one or something, not sure if would I get notifications. Its only for assigning copilot to issues - communication please with my main (this) account.)