rename "Test Extension" #703

“Test Extension” is unfortunately named:

• file names for this extension become confusing, e.g. test_test_extension or test_extension_test, regardless of the chosen naming convention.
• files that implement this extension (e.g. test_extension, test_extension_types ) imply that these are test files, not actual implementation files.
• even though this extension can be used for testing (or may be intended for interoperability testing), the “test” prefix is still misleading. an extension’s name should describe what the extension is, not who, where, or how it is used.
• if the extension name is used without the word “extension”, it becomes unclear what is being referenced. for example, “partial messages” does not require the word “extension”, because it is already clear that it refers to an extension (assuming prior familiarity).

better name suggestion:

• Hola - personal opinion: non english word makes better sense as name of extension (this is not my first language)
• Hello
• HolaInterop - if we need to have where this is used
• HelloInterop
• HelloOnce - because it sends "Hello" message once
• "Experimetal" + "Hola/Hello/HelloOnce"
• etc...