Move String methods into own module

[ST-DDT]

Clear and concise description of the problem

Currently the string methods are spread in multiple modules and it isn't easy to guess them correctly.

Suggested solution

• All random string methods should be in their own module
• The old methods are preserved for a full major version (deprecated)

Alternative

No response

Additional context

No response

[ST-DDT]

See also #805

[ST-DDT]

Blocked by #932 / #1291