chore: remove deprecated multicodec package

[nickreynolds]

What issue is this PR fixing

removes multicodec package which was deprecated and refactors bytesToMultibase util function to support secp256k keys

Quality

Check all that apply:

• [X] I want these changes to be integrated
• [X] I successfully ran pnpm i, pnpm build, pnpm test, pnpm test:browser locally.
• [X] I allow my PR to be updated by the reviewers (to speed up the review process).
• [ ] I added unit tests.
• [ ] I added integration tests.
• [ ] I did not add automated tests because _____, and I am aware that a PR without tests will likely get rejected.

[codecov[bot]]

Codecov Report

Patch coverage: 57.14% and project coverage change: -0.04% :warning:

Comparison is base (e2efa88) 84.92% compared to head (8307cd7) 84.88%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## next #1245 +/- ## ========================================== - Coverage 84.92% 84.88% -0.04% ========================================== Files 167 167 Lines 18120 18120 Branches 2036 2040 +4 ========================================== - Hits 15388 15382 -6 - Misses 2732 2738 +6 ``` | [Files Changed](https://app.codecov.io/gh/uport-project/veramo/pull/1245?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uport-project) | Coverage Δ | | |---|---|---| | [packages/utils/src/encodings.ts](https://app.codecov.io/gh/uport-project/veramo/pull/1245?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uport-project#diff-cGFja2FnZXMvdXRpbHMvc3JjL2VuY29kaW5ncy50cw==) | `88.71% <50.00%> (-2.35%)` | :arrow_down: | | [...ackages/did-provider-peer/src/peer-did-provider.ts](https://app.codecov.io/gh/uport-project/veramo/pull/1245?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uport-project#diff-cGFja2FnZXMvZGlkLXByb3ZpZGVyLXBlZXIvc3JjL3BlZXItZGlkLXByb3ZpZGVyLnRz) | `64.28% <60.00%> (-1.39%)` | :arrow_down: | | [packages/did-provider-key/src/key-did-provider.ts](https://app.codecov.io/gh/uport-project/veramo/pull/1245?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uport-project#diff-cGFja2FnZXMvZGlkLXByb3ZpZGVyLWtleS9zcmMva2V5LWRpZC1wcm92aWRlci50cw==) | `76.92% <100.00%> (-0.53%)` | :arrow_down: |

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