Update instrumentation library naming guidance to avoid conflicts between external and otel instrumentations (open-telemetry#4187)

Some package managers (PyPi) don't provide means to reserve namespaces
for projects. We also have a number of **external** instrumentation
libraries in python that follow current guidance and use
`opentelemetry-instrumentation-{component}` naming pattern.

These libraries are hard to distinguish from otel-authored ones. Also,
when someone (legitimately following existing guidance) creates an
external instrumentation package like this, it blocks our ability to
have OTel-authored instrumentation with this 'good' name.

See
open-telemetry/opentelemetry-python-contrib#2759 (comment)
for real-life example.

## Changes

This PR changes the recommendation to:
- otel authored instrumentation should use
`opentelemetry-instrumentation-*` pattern
- external instrumentation should not use this pattern and should prefix
lib name with their company/project/etc name

* ~~[ ] Related issues #~~
* ~~[ ] Related [OTEP(s)](https://github.com/open-telemetry/oteps) #~~
* ~~[ ] Links to the prototypes (when adding or changing features)~~
* [x]
[`CHANGELOG.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CHANGELOG.md)
file updated for non-trivial changes
* ~~[ ]
[`spec-compliance-matrix.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix.md)
updated if necessary~~

---------

Co-authored-by: Armin Ruech <[email protected]>

Author: lmolkova

Diff for: CHANGELOG.md

@@ -32,6 +32,9 @@ release.
 
 ### Common
 
+- Update instrumentation library guidance to avoid naming collisions between external and OTel instrumentations.
+  ([#4187](https://github.com/open-telemetry/opentelemetry-specification/pull/4187))
+
 ### Supplementary Guidelines
 
 ## v1.36.0 (2024-08-12)

Diff for: specification/overview.md

@@ -384,9 +384,17 @@ an [Instrumentation Library](glossary.md#instrumentation-library).
 An instrumentation library should be named to follow any naming conventions of
 the instrumented library (e.g. 'middleware' for a web framework).
 
-If there is no established name, the recommendation is to prefix packages
-with "opentelemetry-instrumentation", followed by the instrumented library
-name itself. Examples include:
+For instrumentation hosted in OpenTelemetry repositories, the recommendation is
+to prefix packages with "opentelemetry-instrumentation", followed by the
+instrumented library name itself. Examples include:
 
 * opentelemetry-instrumentation-flask (Python)
 * @opentelemetry/instrumentation-grpc (Javascript)
+
+Instrumentations libraries not hosted by OpenTelemetry should avoid
+potential naming collisions with OpenTelemetry-hosted packages.
+For example, they may prefix instrumentation package name with their company or
+project name:
+
+* {company}-opentelemetry-instrumentation-{component} (Python)
+* @{company}/opentelemetry-instrumentation-{component} (Javascript)