remove Type(), Route(), GetSignBytes() (removed from sdk.Msg interface)

[colin-axner]

Description

SDK has removed Type() Route() and GetSignBytes() from the Msg interface. Those functions are still needed for the transfer message which supports amino signing. They would be unused for all other message types.

I figure we might as well remove what we can before 1.0.0 since after that we would need to wait for a major version release to remove old APIs

closes: #159

---

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• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov-commenter]

Codecov Report

Merging #161 (4084225) into main (6537f24) will increase coverage by 0.48%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #161      +/-   ##
==========================================
+ Coverage   78.48%   78.97%   +0.48%     
==========================================
  Files         109      109              
  Lines        6488     6434      -54     
==========================================
- Hits         5092     5081      -11     
+ Misses       1038      995      -43     
  Partials      358      358              

Impacted Files	Coverage Δ
modules/core/02-client/types/msgs.go	76.64% <ø> (+6.17%)	⬆️
modules/core/03-connection/types/msgs.go	85.81% <ø> (+4.11%)	⬆️
modules/core/04-channel/types/msgs.go	77.02% <ø> (+6.07%)	⬆️
modules/core/keeper/msg_server.go	64.89% <100.00%> (ø)

[tac0turtle]

LGTM