Prevent use of double sub-path and incorrect asset path in manifest

[zeripath]

MakeAbsoluteAssetURL should just url join the static url prefix on to appurl
if it is not an absolute path - this is because StaticURLPrefix is an absolute
prefix not a relative prefix to the app sub url.

Fix #14422
Close #14427

Signed-off-by: Andrew Thornton art27@cantab.net

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@2e8ce1e). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master   #14827   +/-   ##
=========================================
  Coverage          ?   42.23%           
=========================================
  Files             ?      771           
  Lines             ?    82181           
  Branches          ?        0           
=========================================
  Hits              ?    34711           
  Misses            ?    41821           
  Partials          ?     5649           

Impacted Files	Coverage Δ
modules/setting/setting.go	48.93% <100.00%> (ø)

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[6543]

@uli-heller can you also verify this patch fix it for you too?

[uli-heller]

I'm about to verify the patch against master, hope this is fine:

$ git log --oneline
f8efcf6e6 (HEAD -> test-pull-request-14827, origin/test-pull-request-14827) Merge branch 'master' into fix-14422-make-absolute-asset-url-fixes
4e7e3bd4b (upstream/master, upstream/HEAD, upstream-master) [skip ci] Updated licenses and gitignores
5c4342b6f Prevent use of double sub-path and incorrect asset path in manifest
3d8b5ad5f Fix a couple of CommentAsPatch issues.  (#14804)
...

[uli-heller]

To me, all fine

• commit id shown within footer
• url contains a context (/gitea)
• when querying the logo.png, the context shows up within the url just once