chore: generalize the instrumentation file name

[rauno56]

Which problem is this PR solving?

It renames the files containing the instrumentation logic to instrumentation.ts in every package to generalize the folder structure a bit.

Short description of the changes

There was a discussion here that having those unified would be beneficial. I agree with @obecny on that.

[codecov]

Codecov Report

Merging #479 (4cce391) into main (0040ab8) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #479   +/-   ##
=======================================
  Coverage   95.26%   95.26%           
=======================================
  Files         140      140           
  Lines        8399     8399           
  Branches      815      815           
=======================================
  Hits         8001     8001           
  Misses        398      398           

Impacted Files	Coverage Δ
...try-instrumentation-graphql/src/instrumentation.ts	92.30% <ø> (ø)
...elemetry-instrumentation-pg/src/instrumentation.ts	82.29% <ø> (ø)
...node/opentelemetry-instrumentation-pg/src/utils.ts	97.26% <100.00%> (ø)
...ode/opentelemetry-instrumentation-hapi/src/hapi.ts
...entelemetry-instrumentation-mongodb/src/mongodb.ts
...umentation-user-interaction/src/userInteraction.ts
...entelemetry-instrumentation-express/src/express.ts
...entelemetry-instrumentation-winston/src/winston.ts
node/opentelemetry-instrumentation-net/src/net.ts
...metry-instrumentation-aws-lambda/src/aws-lambda.ts
... and 23 more