[TS-fetch - v2] Add support for bearer token authentication

[johan-jnn]

Based on #9493

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: 3.0.0 branch for changes related to OpenAPI spec 3.0. Default: master.

Description of the PR

Based on how PHP template deals with Bearer auth, I did the same in the typescript-fetch mustache template.

The token should be passed to the accessToken configuration key (as in the php code). If a function is given, we call it without the scope argument (as authorized in the definition of accessToken).

Notes

Maybe I should add some java tests to test this, but idk how to write java in such big project.
This means I ran the ./bin/typescript-fetch-petstore.sh (through run-in-docker.sh) but did not test if it actually works.