Add support for instrumenting bun library

[hypnoglow]

Is your feature request related to a problem? Please describe.

bun is a successor of go-pg. There is already a module for go-pg, but there is no module for bun.

Describe the solution you'd like

Package module/apmbun that provides instumentation.

Describe alternatives you've considered

Alternative is to use apmsql, but it is harder to integrate and requires changing how bun is used in the application.

Additional context