Add region, account_id properties to OMS driver URL

[zhouxinyu]

Currently, OMS driver URL schema is:

oms:<driver_type>://<access_point>[,<access_point>,...]/<namespace>

The only user-oriented property is namespace, which is not enough to handle many complicated scenarios, like multiple tenants, environment isolation, AB tests, etc.

Consider adding region and account_id properties to OMS driver URL.

[vintagewang]

username is equivalent to AppId，ProjectId。
It is used to identify the resource belongs to who

[zhouxinyu]

New alternative schema:

oms:<driver_type>://<account_id>@<access_point>[,<access_point>,...]/<region>:<namespace>

For example：

oms:rocketmq://alice@openmessaging.cloud,rocketmq.org/us-east:default_space
oms:rocketmq://bob@openmessaging.cloud/us-east:default_space

[zhouxinyu]

Access point schema:

https://github.com/openmessaging/specification/blob/master/oms_access_point_schema.md

[vongosling]

URI still include the password of the username(accout_id).