run dir: write detailed log file

For each run on a trial, create a log target that logs to a file in the run
dir. Set all levels to DBG in that log target.

Related: OS#2206
Change-Id: Ie7279aeaf32950f85d4145abdc917024003d1d99
diff --git a/src/osmo_gsm_tester/log.py b/src/osmo_gsm_tester/log.py
index 10108bc..0da9bd5 100644
--- a/src/osmo_gsm_tester/log.py
+++ b/src/osmo_gsm_tester/log.py
@@ -83,6 +83,9 @@
         self.style()
         LogTarget.all_targets.append(self)
 
+    def remove(self):
+        LogTarget.all_targets.remove(self)
+
     def style(self, time=True, time_fmt=DATEFMT, category=True, level=True, origin=True, origin_width=32, src=True, trace=False):
         '''
         set all logging format aspects, to defaults if not passed: