Add pandas and sqlalchemy python modules

As discussed in ATLINFR-2962 the pytools is no more in LCG_95. With this MR I'm adding two python modules from LCG so that we can use them in the Athena nightlies. The additional files are kept to a minimum and seems to work fine testing locally. However, I'd be happy to hear comments on them. Let me tag @akraszna explicitly.