Indent Options and Clarify Tab Width

Description

This is a near clone of #147, but git got messed up on that branch. This PR improves that branch anyways.

This enables configuration of the behavior when the tab key is pressed. Previously all tabs were converted to spaces and inserted tabWidth spaces in place of the tab character. This PR clarifies that the tabWidth parameter should be used for the visual width of tabs, and adds an indentOption parameter that specifies how to handle inserting tab characters.

Adds an IndentOption enum with two cases for this behavior:

spaces(count: Int)
tab

If spaces(count: Int) is specified, the editor will insert the given number of spaces when the tab key is pressed, otherwise the tab character will be kept.

Related Issues

80 - Does not close, needs an additional PR for the tab width setting.

Checklist

[x] I read and understood the contributing guide as well as the code of conduct
[x] The issues this PR addresses are related to each other
[x] My changes generate no new warnings
[x] My code builds and runs on my machine
[x] My changes are all related to the related issue above
[x] I documented my code

Screenshots

https://user-images.githubusercontent.com/35942988/228014785-85a20e2e-0465-4767-9d53-b97b4df2e11e.mov

CodeEditApp / CodeEditSourceEditor