Release candidate 1.0

[danielhuppmann]

This PR prepares the package for release 1.0, to follow immediately upon the publication of the pyam manuscript in Open Research Europe.

The PR implements the following changes:

• remove all functions marked as deprecated and update tests accordingly
• clean up the release notes to start with a clean slate
• update the Readme and docs to reference the new manuscript

[codecov]

Codecov Report

Merging #553 (08bfe2d) into main (59f46c8) will increase coverage by 0.0%.
The diff coverage is 100.0%.

@@          Coverage Diff          @@
##            main    #553   +/-   ##
=====================================
  Coverage   93.5%   93.6%           
=====================================
  Files         48      48           
  Lines       5321    5242   -79     
=====================================
- Hits        4979    4909   -70     
+ Misses       342     333    -9     

Impacted Files	Coverage Δ
setup.py	0.0% <ø> (ø)
tests/test_feature_aggregate.py	98.8% <ø> (-0.1%)	⬇️
pyam/core.py	94.3% <100.0%> (+1.8%)	⬆️
pyam/iiasa.py	85.8% <100.0%> (-3.4%)	⬇️
tests/test_core.py	100.0% <100.0%> (ø)
tests/test_feature_append_rename.py	100.0% <100.0%> (ø)
tests/test_iiasa.py	92.6% <100.0%> (-0.2%)	⬇️
tests/test_tutorials.py	94.5% <100.0%> (+1.0%)	⬆️
pyam/logging.py	53.1% <0.0%> (-6.3%)	⬇️

---

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[danielhuppmann]

The docs with this PR are rendered at https://pyam-iamc.readthedocs.io/en/release-rc_1.0/

[gidden]

Minor comments on including JOSS badges still - Otherwise looks g2g!

[danielhuppmann]

Was a bit fiddly to get that all into one line, edited the badges for groups.io and Slack to make it work...

[gidden]

Great, thank you!

[danielhuppmann]

Published successfully on test.pypi.org, see https://test.pypi.org/project/pyam-iamc/1.0.0/