Create the resource module

[soranjh]

Context:
This PR creates the qml.resource module for hosting future-facing functionalities such as resource estimation.

Description of the Change:

• resource module created inside pennylane.
• factorization.py is moved inside qchem.

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit doc/releases/changelog-dev.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[codecov]

Codecov Report

Merging #2796 (b8dceab) into resource_estimation_algorithms (9334aaf) will not change coverage.
The diff coverage is 100.00%.

@@                       Coverage Diff                       @@
##           resource_estimation_algorithms    #2796   +/-   ##
===============================================================
  Coverage                           99.62%   99.62%           
===============================================================
  Files                                 261      261           
  Lines                               21278    21278           
===============================================================
  Hits                                21198    21198           
  Misses                                 80       80           

Impacted Files	Coverage Δ
pennylane/qchem/factorization.py	100.00% <ø> (ø)
pennylane/resource/__init__.py	100.00% <ø> (ø)
pennylane/resource/first_quantization.py	100.00% <ø> (ø)
pennylane/__init__.py	100.00% <100.00%> (ø)
pennylane/qchem/__init__.py	100.00% <100.00%> (ø)
pennylane/resource/second_quantization.py	100.00% <100.00%> (ø)

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