[snap/backend]: added sign and implment announce transfer transaction

[AnthonyLaw]

What was the issue?

• Missing sign transfer transaction

What's the fix?

• Added sign transfer transaction and announced to network.

[codecov[bot]]

Codecov Report

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

Project coverage is 99.09%. Comparing base (6f913d3) to head (7e1d853). Report is 10 commits behind head on snap/symbol.

Additional details and impacted files

[](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol) ```diff @@ Coverage Diff @@ ## snap/symbol #1054 +/- ## =============================================== + Coverage 99.04% 99.09% +0.04% =============================================== Files 42 42 Lines 2310 2418 +108 Branches 298 311 +13 =============================================== + Hits 2288 2396 +108 Misses 22 22 ``` | [Flag](https://app.codecov.io/gh/symbol/product/pull/1054/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol) | Coverage Δ | | |---|---|---| | [snap-frontend](https://app.codecov.io/gh/symbol/product/pull/1054/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol) | `99.02% <100.00%> (+0.03%)` | :arrow_up: | 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=symbol#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/symbol/product/pull/1054?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol) | Coverage Δ | | |---|---|---| | [snap/backend/src/index.js](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Fbackend%2Fsrc%2Findex.js&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9iYWNrZW5kL3NyYy9pbmRleC5qcw==) | `100.00% <100.00%> (ø)` | | | [snap/backend/src/utils/accountUtils.js](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Fbackend%2Fsrc%2Futils%2FaccountUtils.js&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9iYWNrZW5kL3NyYy91dGlscy9hY2NvdW50VXRpbHMuanM=) | `99.17% <100.00%> (+0.29%)` | :arrow_up: | | [snap/frontend/components/FeeMultiplier/index.jsx](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Ffrontend%2Fcomponents%2FFeeMultiplier%2Findex.jsx&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9mcm9udGVuZC9jb21wb25lbnRzL0ZlZU11bHRpcGxpZXIvaW5kZXguanN4) | `100.00% <100.00%> (ø)` | | | [...nap/frontend/components/TransferModalBox/index.jsx](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Ffrontend%2Fcomponents%2FTransferModalBox%2Findex.jsx&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9mcm9udGVuZC9jb21wb25lbnRzL1RyYW5zZmVyTW9kYWxCb3gvaW5kZXguanN4) | `96.45% <100.00%> (+0.36%)` | :arrow_up: | | [snap/frontend/utils/helper.js](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Ffrontend%2Futils%2Fhelper.js&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9mcm9udGVuZC91dGlscy9oZWxwZXIuanM=) | `100.00% <100.00%> (ø)` | | | [snap/frontend/utils/snap.js](https://app.codecov.io/gh/symbol/product/pull/1054?src=pr&el=tree&filepath=snap%2Ffrontend%2Futils%2Fsnap.js&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=symbol#diff-c25hcC9mcm9udGVuZC91dGlscy9zbmFwLmpz) | `100.00% <100.00%> (ø)` | |