ENH: (CLIENTARCHIVER) remove offline_data option and replace it with beamline_data

[xresende]

The new machine archiver appliance now access all data history, rendering deprecated access to "offline" data of previous years. In its place this PR adds the option to access PVs data from the beamlines archiver appliance.

... still broken! Example:

c = ClientArchiver()
c.switch_to_beamline_data()
c.connected

fixed! It seems the problem is that when I tried this code at the firsr time the bline archiver had not implemented the secure interface yet ("https://"). Now it is working...

[fernandohds564]

@xresende, what do you mean by still broken?

[xresende]

@xresende, what do you mean by still broken?

in my computer communication with the beamline archiver using the class (which works with the machine archiver!) is broken. i started this PR but did not have time to investigate why it is broken. it is probably due to access permissions. but it can also be due to a difference is API since the BLine archiver instance is a newer version.

[vellosok75]

Suggested change

	Sets server URL to online data URL and logs out if needed.
	Sets server URL to machine data URL and logs out if needed.

[VitorSouzaLNLS]

I agree with Matheus' suggestion.