[explorer] Deduplicate the token action strings

Summary:
The template is very difficult to maintain and is causing a duplication
as the same parsing already exists.
We can prepare the content on the rust side directly to simplify and
deduplicate the code. The token URL is converted the same way.

Test Plan:

cargo run

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D15957