Add PR template for adding tokens to the reqistry

[alinetskyi]

This change is 

[miladz68]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @masihyeganeh and @ysv)

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.github/pull_request_template.md line 9 at r1 (raw file):

## Author's Checklist ✅

- [ ] **Chose the correct environment folder** (devnet/mainnet/testnet)

Choose

[masihyeganeh]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @alinetskyi and @ysv)

[masihyeganeh]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @alinetskyi, @miladz68, and @ysv)

[miladz68]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ysv)