WIP: Add namespace support to generator

[rikkuness]

A work in progress attempt at a fix for #22 .

This seems to work okay for v1.0 but currently is broken when generating for beta.

The generator runs for beta but I think that it has perhaps conflicts in the names of types? I'm not sure the best way to approach this, should the different namespaces be under their own structure, for example github.com/yaegashi/msgraph.go/beta/callRecords for the microsoft.graph.callRecords namespace?

[DonovanCharpin]

Hi @rikkuness, did you manage to fix this issue?

[kim-at-thirdlight]

This still seems to have issues with item names from the inconsistent renaming of entities ending in Request. If you move the request object name-change logic to exported(), as in:
kim-at-thirdlight@f4ccfc5

This will fix most of the issues. Note this commit is is from a branch that attempted to fix the namespacing issue in a much less elegant manner, please ignore it 😅

There does still seem to be some issues in beta with repeat definitions of DeviceManagementTemplateSettingsCollectionRequest though... I will further look into this