Heads up: upcoming calendar entries format change; request for integrations; time to criticize now

[Vadim Tkachenko]

Hello lurkers,

Now that the economizer is a first class object in HCC, it's time to
integrate it into the schedule (all the code changes will be tracked
here: https://github.com/home-climate-control/dz/issues/240)

I looked at the existing format a bit and realized that it's a bit
long in the tooth (12 years old, to be exact) and could use
improvement as far as integration and interoperability are concerned.
So, to achieve that, I'll be augmenting the calendar entry format in a
backward compatible manner to include the economizer.

Migration summary:

- Currently, event definition goes into "event summary", all new
information except for the event name will be read from "event description";
- Existing calendar entries will work as far as zone temperatures and
settings are concerned;
- Existing calendar entries augmented with additional information in
the description will have the old and new format information merged,
if there is redundant (and possibly conflicting) information in the
summary and in the description, the latter takes precedence and logs
light up with loud warnings;
- To make things easier for integrations, all the data in the event
description will be stored as JSON;
- Not to drag compatibility forever, the new implementation will spit
fully formed configurations you'd be able to copypaste back into the
calendar whenever it encounters mixes, until the moment it is
deprecated and then decommissioned.

Not to get up twice... Depending on Google is something I don't like;
the only other widespread formats I can think of are Apple and
Microsoft, neither of which is acceptable for the same reasons:
privacy, and vendor lock-in. There are Open Source solutions for that,
it would help if anyone here that has used any of them shared their
experience both pro and con - the calendar reader is a pretty simple
piece of code and the new integration will not be far behind as soon
as the provider is selected.

--vt