Add dish direction and "prolonged" obstruction info to the status mode group.
These were added to the grpc service at some point over the last several months.
Only lightly tested, given that my dish no longer reports significant periods of obstruction.
This is related to discussion in issue #27, although it doesn't address that issue in the slightest.
Currently only implemented for sqlite, since with InfluxDB, there is the complication that the InfluxDB server may not be available to query at script start time. Also, it only applies when polling all samples, which is not the default, and even then can be disabled with either --skip-query or --no-counter options.
Remove the crontab instructions from the README, since the periodic loop functionality is probably now a better approach for periodic recording of stats data.
Got broken when I made a separate samples option for bulk history vs history stats. Also, it looks like I never actually implemented support for the --skip-query option.
Since the alert types are determined dynamically from the protocol definition, the status schema may need to be updated even if nothing changed in the scripts, when the dish software adds a new alert type (which just happened, say hello to the "mast_not_near_vertical" alert). This allows the manual override for that case, not just schema version downgrade.
Probably not terribly useful unless someone needs to tunnel through a different network to get to their dish, but it makes testing the dish unreachable case a lot easier. This was complicated a bit by the fact that a channel (and therefor the dish IP and port) is needed to get the list of alert types via reflection due to prior changes.
This exposed some issues with the error message for dish unreachable, so fixed those.
I had only added the one that the Starlink app uses to show obstructions, because it didn't seem like the other one was all that useful, but people seem to be interested in studying the difference between the 2, so might as well have it. This is in the obstruction_detail group, along with the other one. I'm kinda regretting naming the first one as I did, though, because it's now a little confusing between my naming and the naming in the grpc message.
Since this is a new field, also had to implement schema updates for the sqlite script.
I'm sure this isn't a particularly optimal implementation, but it's functional.
This required exporting knowledge about the types that will be returned per field from starlink_grpc and moving things around a little in dish_common.
