## Describe your changes
In https://github.com/neondatabase/cloud/issues/4354 we are making
scheduling of projects based on available disk space and overcommit, so
we need to know disk size and just in case instance type of the
pageserver
## Issue ticket number and link
https://github.com/neondatabase/cloud/issues/4354
## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] ~If it is a core feature, I have added thorough tests.~
- [ ] ~Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?~
- [ ] ~If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.~
I moved management API v2 to ogen and the generated code seems to be
more strict about content type. Let's set it properly as it is json
after all
## Describe your changes
## Issue ticket number and link
## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
