Export / Import as XML

Merge branch 'master' into mysql_support

(refs #1154)Fix path of request to the branch protection API

Remove PLUGIN table from export target

Fix solidbase plugin support

Remove unnecessary files

Update pre-condition checking

Merge branch 'master' into mysql_support ...

# Conflicts:
#	src/main/resources/update/3_13.sql
#	src/main/scala/gitbucket/core/servlet/AutoUpdate.scala

Add Version 3.14

Merge branch 'webhook-content-type' of https://github.com/McFoggy/gitbucket into McFoggy-webhook-content-type ...

# Conflicts:
#	src/main/scala/gitbucket/core/service/WebHookService.scala
#	src/main/twirl/gitbucket/core/settings/edithooks.scala.html

Fix SQL for PostgreSQL

Display database url at the system setting console

Fixup

Fix table order in the exported sql file

Fix for PostgreSQL support

Update PostgreSQL configuration example

Remove unnecessary file

Use COALESCE instead of IFNULL

Add PostgreSQL support

Update MySQL configuration example

Data import is available

Working for data import tool

Add data import form

Database export tool is available

Start to implement the database export tool

Start to implement the database export tool

Backup H2 data files before migration to 4.0 if files exist

Fix comment

Experimental support for MySQL is available!

Use ${currentDateTime}