[shelly] Add support for Shelly Plus Mini series, Pro EM-50 and various bug fixes...

[shelly] Add support for Shelly Plus Mini series, Pro EM-50 and various bug fixes (#15205)

* Shelly BLU support, various fixes
* Shelly Dimmer US added
* Reference to org.eclipse.jetty.websocket updated to 9.4.50.v20221201
* Support for Shelly Wall Display added
* Fixed #15052: channel totalKWH and totalRetruned: correct value is kw/h
(API value needs to be converted from Watt/Min to kw/h)
* Regular power meter returns Watt/Min, the EM/3EM meter returns W/h; this
needs to be handled differently
* Gen2 power meter returns Watt, which needs to be converted to W/h
(and then gets converted to kw&/h for the channel update)
* bug fixes around channel creation, some xml channel declarations fixed
* Support for 1Mini, 1PM Mini and PM Mini added
* Avoid NPE for devices having relay(s), but no meter (like Pro 2); README
updated
* Shelly Pro 3EM-50 added; fixes #15151, #15152 and more
* fix #15218 (only 1 device#resetTotals channel)
* Fix Pro EM50 (it's not a 3EM-50): thing type name is now shellyproem50,
use EM1DataDeleteAllData method rather then EMDataDeleteAllData
* <connection>local</connection> added to addon.xml
* channel group names for i4 fixed, Plus-Roller now has voltage

Signed-off-by: Markus Michels <markus7017@gmail.com>