Add backend jwt policy template

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 20.26%. Comparing base (a621c23) to head (6e9d1d1). Report is 6 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #13469 +/- ## ============================================ - Coverage 20.53% 20.26% -0.27% + Complexity 1040 1033 -7 ============================================ Files 254 254 Lines 11495 11495 Branches 1200 1200 ============================================ - Hits 2360 2330 -30 - Misses 9115 9136 +21 - Partials 20 29 +9 ``` | [Flag](https://app.codecov.io/gh/wso2/product-apim/pull/13469/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=wso2) | Coverage Δ | | |---|---|---| | [integration_tests](https://app.codecov.io/gh/wso2/product-apim/pull/13469/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=wso2) | `20.26% <ø> (-0.27%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=wso2#carryforward-flags-in-the-pull-request-comment) to find out more.

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