docs: remove redundant migration text from READMEs

[blumamir]

instrumentations aws-sdk, mongoose and amqplib where originally hosted in aspect repo https://github.com/aspecto-io/opentelemetry-ext-js

When upstreaming them to the contrib repo, I added migration instructions for people who might be migrating from the old to the new package.

Since few years has pass, I think this info is no longer relevant or needed in the README

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.30%. Comparing base (dfb2dff) to head (1353f47).
Report is 169 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2243      +/-   ##
==========================================
- Coverage   90.97%   90.30%   -0.68%     
==========================================
  Files         146      147       +1     
  Lines        7492     7263     -229     
  Branches     1502     1509       +7     
==========================================
- Hits         6816     6559     -257     
- Misses        676      704      +28     

see 57 files with indirect coverage changes

[trentm]

LGTM.

Should instr-socket.io be done as well?
https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/plugins/node/instrumentation-socket.io/README.md#migration-from-opentelemetry-instrumentation-socketio

[pichlermarc]

LGTM.

Should instr-socket.io be done as well? https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/plugins/node/instrumentation-socket.io/README.md#migration-from-opentelemetry-instrumentation-socketio

Yes, I think we should also do the same to that package.

[blumamir]

LGTM.

Should instr-socket.io be done as well? https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/plugins/node/instrumentation-socket.io/README.md#migration-from-opentelemetry-instrumentation-socketio

removed the text from socket.io as well. Thanks!