jsonrpc: number constant types which could be converted to enum (typescript string union)

[Simon-Laux]

continuation of https://github.com/chatmail/core/issues/7029

• [x] ChatType https://github.com/chatmail/core/pull/7285
• [ ] ProviderInfo status
• [ ] MessageState (don't forget to also change return type of summary_status)

maybe:

• push notification state, but for that dc_get_push_state api would need to be implemented to jsonrpc first
  • done in https://github.com/chatmail/core/pull/7356
• summary prefix/meaning (DC_TEXT1_) would need to be first added to jsonrpc api, because it does not return the type yet, it just returns the rendered string as part of the output, but not the machine readable form.
  • (do we even need that? for what is it used on the other platforms)

not applicable:

• Connectivity State: Because the states are defined as ranges and all UIs also treat it as ranges (at time of writing)