Install + package remsim-apitool as separate sub-package

As the script depends on python3, let's put it into a new
osmo-remsim-apitool package.

As we're installing the tool system-wide, rename it from
remsim-apitool.py to osmo-remsim-apitool.

Closes: OS#5612
Change-Id: I11d779f66833b5294ffeb422ce6b2a705719a899
diff --git a/debian/control b/debian/control
index 7a847b8..b899b0f 100644
--- a/debian/control
+++ b/debian/control
@@ -51,6 +51,15 @@
  it maintains a list of clients + bankds connected to it, as well as the
  dynamic SIM card mappings between them.
 
+Package: osmo-remsim-apitool
+Architecture: any
+Multi-Arch: same
+Depends: ${misc:Depends}, python3
+Description: Osmocom Remote SIM - API tool for server
+ This is a small python tool for generating API requests to remsim-server,
+ which can be used by the system administrator to introspect and/or modify
+ the state (mostly slotmaps).
+
 Package: osmo-remsim-bankd
 Architecture: any
 Multi-Arch: same