location: add all.py, using takeout/gpslogger/ip (#237)

* location: add all.py, using takeout/gpslogger/ip, update docs

my/ip/all.py

@@ -0,0 +1,29 @@
+"""
+An example all.py stub module that provides ip data
+
+To use this, you'd add IP providers that yield IPs to the 'ips' function
+
+For an example of how this could be used, see https://github.com/seanbreckenridge/HPI/tree/master/my/ip
+"""
+
+REQUIRES = ["git+https://github.com/seanbreckenridge/ipgeocache"]
+
+
+from typing import Iterator
+
+from my.core.common import Stats, warn_if_empty
+
+from .common import IP
+
+
+@warn_if_empty
+def ips() -> Iterator[IP]:
+    yield from ()
+
+
+def stats() -> Stats:
+    from my.core import stat
+
+    return {
+        **stat(ips),
+    }