Update how to get help

@heriche @akhan what do you think about my proposed changes?

my idea would be that we are only telling them about all the PPMS booking stuff once we looked at their mail and had a short chat about how to best help them.

also this would make it more accessible for supporting people that do not (yet) have an EMBL or PPMS account.

in addition, I find now that providing these open booking options in PPMS is a bit of a burden for us because we have to always update them for availability of staff (holidays, sickness, etc...). While being a bit more work for us, getting back to the people with appointment suggestions by mail would not have this issue.