meta/sql: use binary as column type for xattr

[davies]

close #4803

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 54.52%. Comparing base (fc2d91d) to head (878d184).
⚠️ Report is 798 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4873      +/-   ##
==========================================
+ Coverage   44.86%   54.52%   +9.65%     
==========================================
  Files         158      160       +2     
  Lines       42872    43351     +479     
==========================================
+ Hits        19233    23635    +4402     
+ Misses      21228    17036    -4192     
- Partials     2411     2680     +269     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[SandyXSD]

We have to update the table schema manually if we want this change, see:
https://juicefs.com/docs/community/release_notes/#juicefs-v10

[SandyXSD]

# sqlite as the meta engine
# old version
root@dev:/mnt/jfs# xattr -w testkey testval f
root@dev:/mnt/jfs# xattr -l f
testkey: testval
# with this PR
root@dev:/mnt/jfs# xattr -l f
No such xattr: testkey

[CLAassistant]

All committers have signed the CLA.