Plugin optimization

[piotrWichlinskiSoftwaremind]

@diocas

• Cut down the number of requests - done mainly by removing duplicated stat information requests and passing stat info down to lower methods

• To fix a bug (on local and localhome drivers) I had to duplicate stat requests, it's only for local dev env so I have introduced a temporary config value dev_env.

• Fixed frontend - the correct way to handle drives (this cuts down requests and drive names cs3drive: is automatically removed on the frontend side, except one external place - our infobox)

• Fixed lock possible bug with getting locks - a simple name for locks, fixed a possible issue with get_lock

• Add is_editor method (check if the user can edit a file) - we don't need a whole rendered share list to get permission for one file, adding filters to shares received (OCM's are missing Filters, it will be reported with other bugs that I found)

• Use filters in shares to get the correct share

• Remove checking drives names in the backend (we don't need it anymore, there is only one place that reuses drive names incorrectly and it's handled in frontend)

• Adjusted some tests for the changes from the code refactor

[diocas]

This looks to be fixing some open issues, no? (IIRC, there was this 500 when checking a file because we were failing on the parent). Please update the description to close them.