realm import: Convert the authentication_methods from list to bitfield.
realm import: Convert the authentication_methods from list to bitfield.

This properly reflects how this is stored in the DB.

Tweaked by tabbott to use a proper function.

tommyip/zulip,andersk/zulip,kou/zulip,dhcrzf/zulip,tommyip/zulip,brockwhittaker/zulip,hackerkid/zulip,kou/zulip,brockwhittaker/zulip,dhcrzf/zulip,kou/zulip,rishig/zulip,andersk/zulip,brockwhittaker/zulip,andersk/zulip,rht/zulip,synicalsyntax/zulip,dhcrzf/zulip,Galexrt/zulip,zulip/zulip,jackrzhang/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,timabbott/zulip,synicalsyntax/zulip,showell/zulip,rht/zulip,synicalsyntax/zulip,shubhamdhama/zulip,punchagan/zulip,punchagan/zulip,andersk/zulip,shubhamdhama/zulip,tommyip/zulip,mahim97/zulip,timabbott/zulip,hackerkid/zulip,dhcrzf/zulip,tommyip/zulip,hackerkid/zulip,rishig/zulip,brockwhittaker/zulip,Galexrt/zulip,Galexrt/zulip,eeshangarg/zulip,brainwane/zulip,brainwane/zulip,zulip/zulip,punchagan/zulip,brockwhittaker/zulip,brainwane/zulip,Galexrt/zulip,andersk/zulip,rishig/zulip,brainwane/zulip,kou/zulip,mahim97/zulip,timabbott/zulip,showell/zulip,shubhamdhama/zulip,shubhamdhama/zulip,rishig/zulip,rht/zulip,andersk/zulip,jackrzhang/zulip,rht/zulip,zulip/zulip,mahim97/zulip,timabbott/zulip,eeshangarg/zulip,synicalsyntax/zulip,Galexrt/zulip,shubhamdhama/zulip,mahim97/zulip,synicalsyntax/zulip,eeshangarg/zulip,tommyip/zulip,mahim97/zulip,shubhamdhama/zulip,hackerkid/zulip,jackrzhang/zulip,kou/zulip,rht/zulip,hackerkid/zulip,hackerkid/zulip,dhcrzf/zulip,tommyip/zulip,zulip/zulip,showell/zulip,jackrzhang/zulip,tommyip/zulip,brainwane/zulip,rht/zulip,showell/zulip,showell/zulip,showell/zulip,eeshangarg/zulip,showell/zulip,kou/zulip,brockwhittaker/zulip,dhcrzf/zulip,punchagan/zulip,jackrzhang/zulip,rishig/zulip,punchagan/zulip,timabbott/zulip,brainwane/zulip,mahim97/zulip,eeshangarg/zulip,eeshangarg/zulip,rht/zulip,punchagan/zulip,Galexrt/zulip,synicalsyntax/zulip,timabbott/zulip,jackrzhang/zulip,jackrzhang/zulip,Galexrt/zulip,zulip/zulip,rishig/zulip,rishig/zulip,hackerkid/zulip,synicalsyntax/zulip,timabbott/zulip,brainwane/zulip,zulip/zulip,shubhamdhama/zulip,dhcrzf/zulip,zulip/zulip,punchagan/zulip