Simplify DateTimeType handling

[jlaur]

This is a cleanup only and does not change functionality when openhab/openhab-core#3583 has first been merged. The core PR discards time-zone from DateTimeType, thus binding code can be simplified:

• Instantiations from ZonedDateTime using either time-zone from TimeZoneProvider or ZoneId.systemDefault() have been simplified to use Instant. In some cases this entirely eliminated the need for TimeZoneProvider, which has then been removed.
• Usages of deprecated methods toZone and toLocaleZone have been removed.
• Usages of deprecated method getZonedDateTime() have been removed. In cases where time-zone is needed, getZonedDateTime(ZoneId.systemDefault()) is now explicitly called.

Related to openhab/openhab-core#3583

[jlaur]

Not merging it will make 4.3.x patches harder due to the amount of files and possible conflicts. WDYT?

Perhaps one way to mitigate this issue would be to merge it in the very beginning of the 5.0 development cycle and avoid squash-merging. When preserving all commits, it would be a simple matter of cherry-picking the commit for a specific binding before cherry-picking the patch commit. WDYT?

I have carefully crafted one commit per binding. This makes it easier for me to handle potential conflicts, and it also allowed me to quickly cherry-pick a single commit into #17872 for fixing a CI test. It has also helped me keeping a clean history by squashing commits when I had to do multiple iterations for a single binding.

Just a small reminder about this suggestion, did you consider it @lsiepel?

[lsiepel]

ps one way to mitigate this issue would be to merge it in the very beginning of the 5.0 development cycle and avoid squash-merging. When preserving all commits, it would be a simple matter of cherry-picking the commit for a specific binding before cherry-pickin

Yes, i think that is the best. As you where still adding changes, i waited. Does it mean this PR is finished now?

[jlaur]

As you where still adding changes, i waited. Does it mean this PR is finished now?

Sorry about that - I found a few more places. 😉

In the last iteration, I was searching for "new DateTimeType(" looking for places where ZonedDateTime was used unneededly. Some of the results were quite hidden and I needed to open the specific bindings into my IDE for closer inspection, which then lead to a few more findings.

I probably missed a few, but I think the PR is ready to be merged now.

[jlaur]

@lsiepel - thanks for the review, I know it was quite a lot of files.

[lsiepel]

back ported commit for Network binding. (i can't set a patch anywhere, so i leave this message here)