parse_qs: improved parsing of query string for obfuscation.

remote-clone: obfuscate also given query string paramas that RhodeCode uses. Fixes #4668

remote-clones: make sure we always use obfuscated url inside logs. This prevents leaking some secrets into logging data. Fixes #4668

svn-backend: add handling of rename file as changes. Fixes #4258

git-version: strip the info returned from subcall to remove newline character.

http: added service backend for testing communication, and extracting vcsserver version via remote calls.

backends: implemented functions for fetching backend versions via remote calls. Ref: #4276

subrepo: Apply mercurial sub repository patch.

subrepo: Turn off interactive mode when merging mercurial repo. If there is a merge conflict in the sub repositories mercurial will prompt the used to decide which version to use.

subrepo: Add custom exception to indicate subrepo merge conflict.