Make commit author length configurable

[stefanhaller]

• PR Description

Following up on #3625, make it possible to configure the length of the author names in the Commits view by setting gui.commitAuthorFormat to truncateTo:<n,m>, where n is the length in the normal view and m the length in the expanded view.

• Please check if the PR fulfills these requirements

• [x] Cheatsheets are up-to-date (run go generate ./...)

• [x] Code has been formatted (see here)

• [x] Tests have been added/updated (see here for the integration test guide)

• [ ] Text is internationalised (see here)

• [x] Docs have been updated if necessary

• [x] You've read through your own file changes for silly mistakes etc

[codacy-production[bot]]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
Report missing for 3af545daf7cf6458e8efd324012047ce688f08e6[^1]	:white_check_mark: 55.10%

Coverage variation details

| | Coverable lines | Covered lines | Coverage | | ------------- | ------------- | ------------- | ------------- | | Common ancestor commit (3af545daf7cf6458e8efd324012047ce688f08e6) | Report Missing | Report Missing | Report Missing | | | Head commit (c389cead3ad03f7ec35dca27cc893a072dc3607e) | 52099 | 45031 | 86.43% | **Coverage variation** is the difference between the coverage for the head and common ancestor commits of the pull request branch: ` - `

Diff coverage details

| | Coverable lines | Covered lines | Diff coverage | | ------------- | ------------- | ------------- | ------------- | | Pull request (#3665) | 49 | 27 | **55.10%** | **Diff coverage** is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: `/ * 100%`

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_{Codacy stopped sending the deprecated coverage status on June 5th, 2024. Learn more} [^1]: Codacy didn't receive coverage data for the commit, or there was an error processing the received data. Check your integration for errors and validate that your coverage setup is correct.

[jesseduffield]

As discussed on discord, I don't like embedding multiple values in a single config key (in this case the n and m in truncate:n,m. I would prefer to have a commitAuthorShortLength and commitAuthorLongLength key. As @stefanhaller suggested, if we do this we can do away with the commitAuthorFormat key entirely and I think that's a good idea.

[stefanhaller]

Closing this in favor of #3688.