provider/mysql: user and grant resources (#7656)

* provider/mysql: User Resource

This commit introduces a mysql_user resource. It includes basic
functionality of adding a user@host along with a password.

* provider/mysql: Grant Resource

This commit introduces a mysql_grant resource. It can grant a set
of privileges to a user against a whole database.

* provider/mysql: Adding documentation for user and grant resources

r/grant.html.markdown

@@ -0,0 +1,52 @@
+---
+layout: "mysql"
+page_title: "MySQL: mysql_grant"
+sidebar_current: "docs-mysql-resource-grant"
+description: |-
+  Creates and manages privileges given to a user on a MySQL server
+---
+
+# mysql\_grant
+
+The ``mysql_grant`` resource creates and manages privileges given to
+a user on a MySQL server.
+
+## Example Usage
+
+```
+resource "mysql_user" "jdoe" {
+    user = "jdoe"
+    host = "example.com"
+    password = "password"
+}
+
+resource "mysql_grant" "jdoe" {
+    user = "${mysql_user.jdoe.user}"
+    host = "${mysql_user.jdoe.host}"
+    database = "app"
+    privileges = ["SELECT", "UPDATE"]
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `user` - (Required) The name of the user.
+
+* `host` - (Optional) The source host of the user. Defaults to "localhost".
+
+* `database` - (Required) The database to grant privileges on. At this time,
+  privileges are given to all tables on the database (`mydb.*`).
+
+* `privileges` - (Required) A list of privileges to grant to the user. Refer
+  to a list of privileges (such as
+  [here](https://dev.mysql.com/doc/refman/5.5/en/grant.html)) for applicable
+  privileges.
+
+* `grant` - (Optional) Whether to also give the user privileges to grant
+  the same privileges to other users.
+
+## Attributes Reference
+
+No further attributes are exported.

r/user.html.markdown

@@ -0,0 +1,37 @@
+---
+layout: "mysql"
+page_title: "MySQL: mysql_user"
+sidebar_current: "docs-mysql-resource-user"
+description: |-
+  Creates and manages a user on a MySQL server.
+---
+
+# mysql\_user
+
+The ``mysql_user`` resource creates and manages a user on a MySQL
+server.
+
+## Example Usage
+
+```
+resource "mysql_user" "jdoe" {
+    user = "jdoe"
+    host = "example.com"
+    password = "password"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `user` - (Required) The name of the user.
+
+* `host` - (Optional) The source host of the user. Defaults to "localhost".
+
+* `password` - (Optional) The password of the user. The value of this
+  argument is plain-text so make sure to secure where this is defined.
+
+## Attributes Reference
+
+No further attributes are exported.