Add ru-RU to home template

Small correction

Added: Ability to delete org avatar.

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

Fix grammar in README

- Allow to delete current avatar

Use relative url when showing forked from

Add ability to delete single wiki pages.

Use hand-written SQL to do complex query

Render emojis in more places.

Repo setting to delete and disable wiki

- Remove unused config settings `[picture] service`

Set DefaultBranch to master when importing a new repo.

update README.md

ISSUE_TEMPLATE: suggestion to test at try.gogs.io

I've noticed that a lot of issues cannot be reproduced on http://try.gogs.io,
which either hints about specific database type problems or
hints about bugs which are already solved in the newer version
(as http://try.gogs.io is usually a newer build).

This patch adds the suggestion to test the issue at http://try.gogs.io in
the Github "issue template". The user can answer: "Yes", "No", "Not relevant".

"Not relevant" is an option where testing on http://try.gogs.io makes no sense as
the bug is unrelated to the Web UI or is very specific in nature.