Implement an interface for Distributed-like libraries

[JamesWrigley]

This moves support for Distributed into a package extension and adds an interface for other distributed worker libraries (i.e. DistributedNext.jl) to use to support Revise for their workers. Admittedly the interface is quite... clunky... so I'm open to other ideas. This also required bumping the minimum Julia version to 1.9 to use package extensions.

As a bonus the load times are slightly improved:

# v3.6.4
julia> @time_imports using Revise
      2.7 ms  OrderedCollections
      0.2 ms  UUIDs
      3.8 ms  CodeTracking
               ┌ 0.2 ms JuliaInterpreter.__init__() 
    136.9 ms  JuliaInterpreter 72.95% compilation time
     35.6 ms  LoweredCodeUtils
      0.7 ms  Serialization
               ┌ 0.0 ms Distributed.__init__() 
     31.7 ms  Distributed 71.09% compilation time
               ┌ 0.0 ms NetworkOptions.__init__() 
      2.2 ms  NetworkOptions
      0.4 ms  Printf
               ┌ 0.2 ms MbedTLS_jll.__init__() 
      2.4 ms  MbedTLS_jll
               ┌ 0.1 ms LibSSH2_jll.__init__() 
      2.1 ms  LibSSH2_jll
               ┌ 0.1 ms LibGit2_jll.__init__() 
      2.0 ms  LibGit2_jll
      7.5 ms  LibGit2
               ┌ 0.1 ms Revise.__init__() 
     79.2 ms  Revise

# This PR
julia> @time_imports using Revise
      3.3 ms  OrderedCollections
      3.4 ms  CodeTracking
               ┌ 0.2 ms JuliaInterpreter.__init__() 
    145.1 ms  JuliaInterpreter 73.80% compilation time
     36.3 ms  LoweredCodeUtils
               ┌ 0.1 ms Revise.__init__() 
     80.9 ms  Revise