ROX-33036: add mount related operations

[Molter73]

Description

This was originally going to be about adding just lsm/sb_mount, however while adding this hook it became pretty clear we needed lsm/sb_umount and lsm/move_mount for a comprehensive implementation and it really didn't add too much code, so they are all added in.

These operations are not currently intended to be forwarded via gRPC, they only trigger inode tracking related behavior (scans on new/moved mounts, inode map cleanups on moved/unmounted directories).

The move mount operation shares quite a bit of similarities with rename, so there is a bit of refactoring mixed in so they can be reused while keeping the code clean.

TODO: add integration tests.

Checklist

• Patch has a change log entry OR does not need one.
• Investigated and inspected CI test results
• Updated documentation accordingly

Automated testing

• Added unit tests
• Added integration tests
• Added regression tests

If any of these don't apply, please comment below.

Testing Performed

TODO(replace-me)
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[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 147 lines in your changes missing coverage. Please review.
✅ Project coverage is 31.80%. Comparing base (6e68429) to head (3cc1980).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
fact/src/event/mod.rs	0.00%	103 Missing ⚠️
fact/src/host_scanner.rs	0.00%	44 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1059      +/-   ##
==========================================
- Coverage   32.64%   31.80%   -0.84%     
==========================================
  Files          21       21              
  Lines        2916     2993      +77     
  Branches     2916     2993      +77     
==========================================
  Hits          952      952              
- Misses       1961     2038      +77     
  Partials        3        3              

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