Release notes for 0.74 (#715)

* [WIP] Release notes for `0.74`

Please add your important new features and breaking changes to the release notes by committing to/opening a PR against the `release-notes-0.73` branch. Thank you!

* Start work on 0.74 release notes

* Mention mimetype flag from Darren

Refer to nushell/nushell#7616

* Update 2023-01-10-nushell_0_74.md

* Add image; Fmt (#718)

* Update 2023-01-10-nushell_0_74.md

* type-o

* Update 2023-01-10-nushell_0_74.md

* Add webbedspace's changes (#727)

* Add hide command breaking change

* Remove broken PATH mention

The PR changing append/prepend commands was reverted.

* Add `math eval` removal

* Mention `url encode`

* Mention get/select changes in breaking changes

* update changelog (#733)

* Update 2023-01-10-nushell_0_74.md

* Add new book chapter note

* Refactor breaking changes

* Update 2023-01-10-nushell_0_74.md

* Add detailed changelog

* Update excerpt

Co-authored-by: Jakub Žádník <[email protected]>
Co-authored-by: Darren Schroeder <[email protected]>
Co-authored-by: Leon <[email protected]>
Co-authored-by: Reilly Wood <[email protected]>
Co-authored-by: WindSoilder <[email protected]>