feat: abstract signer to allow for different methods of signing transactions and auth entries #170

Job	Run time
Unit tests (ubuntu-20.04, 1.22)	2m 16s
Integration tests (ubuntu-20.04, 1.22, .CLI.)	2m 30s
Unit tests (ubuntu-22.04, 1.22)	2m 44s
Build (ubuntu-latest, x86_64-unknown-linux-gnu, amd64)	2m 34s
Integration tests (ubuntu-20.04, 1.22, ^Test(([^C])\|(C[^L])\|(CL[^I])).*$)	12m 16s
Build (ubuntu-latest, aarch64-unknown-linux-gnu, arm64)	3m 12s
Integration tests (ubuntu-22.04, 1.22, .CLI.)	3m 1s
Build (macos-latest, x86_64-apple-darwin, amd64)	5m 4s
Integration tests (ubuntu-22.04, 1.22, ^Test(([^C])\|(C[^L])\|(CL[^I])).*$)	12m 23s
Build (macos-latest, aarch64-apple-darwin, arm64)	5m 27s
Build (windows-latest, x86_64-pc-windows-gnu, amd64)	8m 4s
	59m 31s

Provide feedback