Warm up detectors conditionally

[mrakitin]

Current state

Right now the detectors are warmed up unconditionally, that may be an issue if another bsui session is started in parallel with the existing one (whether under the same account or under another account over ssh).

Examples:

• profile_collection/startup/31-xspress3.py

  Line 421 in 98bd720

  xs2.hdf5.warmup()

• profile_collection/startup/34-merlin.py

  Line 232 in 98bd720

  merlin.hdf5.warmup()

Possible solution:

Wrap these calls to warmup() the detectors into the condition to check if we want to touch the beamline or not, using this standard function (still in the #19 PR branch):

profile_collection/startup/00-base.py

Lines 5 to 12 in 20cb0ec

	def if_touch_beamline(envvar="TOUCHBEAMLINE"):
	value = os.environ.get(envvar, "false").lower()
	if value in ("", "n", "no", "f", "false", "off", "0"):
	return False
	elif value in ("y", "yes", "t", "true", "on", "1"):
	return True
	else:
	raise ValueError(f"Unknown value: {value}")