feat(fmt): Expose ConfigurableFormat

[epage]

The goal is to allow people to compose more complex formatting options (e.g. for #349) by exposing the built-in formatting

A breaking change was split out into #361

[coveralls]

Pull Request Test Coverage Report for Build 14204274818

Details

• 17 of 50 (34.0%) changed or added relevant lines in 2 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.7%) to 44.113%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/logger.rs	0	11	0.0%
src/fmt/mod.rs	17	39	43.59%

Files with Coverage Reduction	New Missed Lines	%
src/fmt/mod.rs	3	63.7%

Totals
Change from base Build 14202307123:	-0.7%
Covered Lines:	266
Relevant Lines:	603

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💛 - Coveralls

[djugei]

this seems somewhat redundant, customformat or default format is used, i do not quite understand why both exist at the same time.
tbh i don't fully understand the intent behind this entire pr.

[djugei]

i do not think the builder which modifies defaultformat would ever be useful for any user of the library that wants a custom formatter. no functions interact at all. i think those two should be fully decoupled.

[epage]

this seems somewhat redundant, customformat or default format is used, i do not quite understand why both exist at the same time.
tbh i don't fully understand the intent behind this entire pr.

This PR serves the following roles

• Makes the intent clearer in what is associated with the default formatter and not the custom formatter
• Allows callers to create their own formatters on top of ConfigurableFormat