Add option to specify keys in the connection string for AWS_SIGv4 authentication

[Yury-Fridlyand]

Is your feature request related to a problem? Please describe.
According to the doc, a JDBC driver user should

• Record access/secret keys in file ~/.aws/credentials before trying to connect
  or
• Set env variables called AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY with corresponding values before opening an application to browse the DB (e.g. Tableau Desktop or DBeaver)

I find both options not-user-friendly for a regular user.

Describe the solution you'd like
Add option to specify keys in the connection string as it is already done for username and password
For example:

jdbc:opensearch://https://blah-blah-blah.us-east-1.es.amazonaws.com?auth=AWS_SIGV4&access_key=$AWS_ACCESS_KEY_ID&secret_key=$AWS_SECRET_ACCESS_KEY

UPD: Once both keys are specified in the connection string, the driver shouldn't create an instance of AWSCredentialsProvider. Specified = both keys are not empty and valid (checksum validation if available).

Additional context
It is relevant for JDBC driver and for ODBC if it supports AWS_SIGv4 authentication method