This change corrects a few logging issues:

 * Standardized formatting errors with '%v'.
 * Standardized failure warning word usage.
 * Corrected an instance of using the standard log library when
   the gitea log library should be used instead.

* Add a process.Manager singleton with process.GetManager()

* Use process.GetManager everywhere

* Fix godoc comments for process module

* Increment process counter id after locking the mutex

* Handle user ssh key input better

ssh_key: when user submitted keys had a newline at the end, strings.Split
would have created a slice with an empty last element, and the key type
check would be incorrect. Perhaps a better way is to look for 'ssh-rsa' or
'ssh-dsa' at the beginning of the string, but this is simple.

* ssh_key: correct indentation

- Update import paths from github.com/go-gitea to code.gitea.io
- Fix import path for travis

See https://docs.travis-ci.com/user/languages/go#Go-Import-Path

Unix() already uses UTC as timezone

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

This commit adds the possibibility to use either the native golang
libraries or ssh-keygen to check public keys. The check is adjusted
depending on the settings, so that only supported keys are let through.

This commit also brings back the blacklist feature, which was removed in
7ef9a05588. This allows to blacklist
algorythms or keys based on the key length. This works with the native
and the ssh-keygen way.

Because of #2179 it also includes a way to adjust the path to
ssh-keygen and the working directory for ssh-keygen. With this,
sysadmins should be able to adjust the settings in a way, that SELinux
is okay with it. In the worst case, they can switch to the native
implementation and only loose support for ed25519 keys at the moment.
There are some other places which need adjustment to utilize the
parameters and the native implementation, but this sets the ground work.

This moves the minimum key sizes into the config file, so that anyone
can modify the restrictions.

- routers/admin: add rewrite update hook operation
- conf/locale: update locale file due to ini behavior changes
- cmd/cert_stub.go: remove useless code
- cmd/fix.go: no longer need fix command(at least now)