`{GitHub}`: Add PR template.

[chris-ramon]

Actual

Currently there is no PR template.

Expected

We want to have a PR template so the format is consistent:

Format:

#### Details
- `{component-name}`: <git commit message>.

#### Test Plan
:heavy_check_mark: Tested that the `./bin/test.sh` works as expected:
TBC.

:heavy_check_mark: Tested that the `./bin/dev.sh` works as expected:
TBC.

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