Repace multiple slash in URI

[phil-davis]

If the URI contains multiple slashes, then "be nice to the caller" and replace them with a single slash.
e.g. someone that asks for some URI like:

/////abc/def//ghi/jkl///mno//

any extra slashes with empty between them actually make no difference, and we can "compress" them.

Should help in cases where a client is "accidentally" sending bonus slashes or...

e.g. owncloud/core#33119 (comment)

[codecov]

Codecov Report

Merging #1111 into master will not change coverage.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master    #1111   +/-   ##
=========================================
  Coverage     97.19%   97.19%           
  Complexity     2865     2865           
=========================================
  Files           174      174           
  Lines          8057     8057           
=========================================
  Hits           7831     7831           
  Misses          226      226

Impacted Files	Coverage Δ	Complexity Δ
lib/DAV/Server.php	97.08% <100%> (ø)	191 <0> (ø)	⬇️

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[staabm]

Thanks for the PR. Lgtm

[DeepDiver1975]

shall we backport this to older releases as well? @staabm

[phil-davis]

Backport to 3.2 is in PR #1112
Let me know if older backports are needed.

[staabm]

shall we backport this to older releases as well?

@DeepDiver1975 good idea. go ahead.