* Add MaxDisplayFileSize setting

* Don't show files that are too large

* Localized FileTooLarge

* Change IsFileTooBig => IsFileTooLarge

Executed go fmt

getEngine() not handles DB parameters (#2972) (#2974)

Uses .AllCols() for Update in updateMirror()

Spanish traslation removed

Fixed a wrong way to ommit the --prune option in process.ExecDir() for MirrorUpdate function

Re: issues gogits/gogs#2863 and gogits/gogs#3231

As a result of modifications to the contents of the conf folder, `make bindata`
was run, causing an update to bindata.go.

Meta
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This commit will be rebased onto the 'develop' branch.

Initially proposed by #2376 and fixes #3068 as well.

"is activate" -> "is activated"

Closes #2764

As you included Czech translation to official distribution, I think I'm missing here.
I know, selfish as hell... ;)

Always send user to settings screen to change avatar.
Drops "change_custom_avatar" localized message, keeps "change_avatar"
for the generic one.

NOTE: only changes the en-US locale, as per
https://github.com/gogits/gogs/wiki/Contributing-Code#those-we-do-not-accept

NOTE: requires rebuild of bindata.go to fully see effects

- Update language choose dropdown to fit more languages

Both are possible on explore and admin panel

Collaborators have write access as default, and can be changed via repository
collaboration settings page to change between read, write and admin.

- Allow to delete current avatar

Use hand-written SQL to do complex query

- Remove unused config settings `[picture] service`

Improve test cases, config settings, also show SSH config settings on admin config panel.

This is feature is workaround for #2628 (JumpCloud) and some other services
that allow LDAP search only under BindDN user account, but not allow any LDAP
search query in logged user DN context.

Such approach is an alternative to minimal permissions security pattern for
BindDN user.