Standardize logging

[rm-dr]

This PR replaces tectonic-status-base with tokio's tracing library. Addresses #1152.

The interesting commits are

• 53daa91476191e920f2988a87f45411131dc668d, which converts log calls to the new api;
• and 35369777d07a0c6486a879f7cd6f9dad4e728a03, which implements a new logger

This PR also changes the log-level cli option, replacing default and minimal with the fairly universal debug, info, warn and error log levels. (b9f0aa35df306046ca178a7ae968c47a965aabd0)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 48.72299% with 261 lines in your changes are missing coverage. Please review.

Project coverage is 46.35%. Comparing base (edd49ba) to head (e4e3c85). Report is 4 commits behind head on master.

:exclamation: Current head e4e3c85 differs from pull request most recent head b99cdd5. Consider uploading reports for the commit b99cdd5 to get more accurate results

Files	Patch %	Lines
crates/engine_spx2html/src/emission.rs	0.00%	40 Missing :warning:
src/driver.rs	61.70%	36 Missing :warning:
src/bin/tectonic/v2cli.rs	50.79%	31 Missing :warning:
crates/bridge_core/src/lib.rs	38.77%	30 Missing :warning:
crates/engine_spx2html/src/initialization.rs	0.00%	18 Missing :warning:
crates/engine_spx2html/src/lib.rs	0.00%	13 Missing :warning:
src/bin/tectonic/log.rs	70.45%	13 Missing :warning:
crates/engine_spx2html/src/finalization.rs	0.00%	11 Missing :warning:
crates/bundles/src/cache.rs	63.15%	7 Missing :warning:
crates/engine_spx2html/src/fonts.rs	0.00%	7 Missing :warning:
... and 15 more

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #1158    +/-   ##
========================================
  Coverage   46.35%   46.35%            
========================================
  Files         171      169     -2     
  Lines       65136    64915   -221     
========================================
- Hits        30191    30093    -98     
+ Misses      34945    34822   -123     

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