fs: rebuild zone lifetime while mount

[ywang-wnlo]

#266

[aravind-wdc]

Can you please add a little more context to the commit message to reflect the need for this change or use case where this would be beneficial ?
And have you tested the impact of this change during mount on an almost full filesystem(ZenFS) on a large drive? Since we are going through all extents of all files in foreground I think it would add significant delay during mount, when the filesystem is full or almost full.

And also you need to rebase with base branch.