Add count_resources function

[Jaybsoni]

Context:
Add a function which takes a tape and counts the resources used in the tape to return a Resources object

Description of the Change:
Add a function in resources.py which iterates over the operations in the tape along with additional meta-data
to count the resources for the tape.

[Jaybsoni]

[sc-36750]

[github-actions]

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

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[codecov]

Codecov Report

Merging #3996 (917cb50) into master (dd664ef) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3996   +/-   ##
=======================================
  Coverage   99.58%   99.58%           
=======================================
  Files         351      351           
  Lines       30755    30766   +11     
=======================================
+ Hits        30626    30637   +11     
  Misses        129      129           

Impacted Files	Coverage Δ
pennylane/resource/resource.py	100.00% <100.00%> (ø)

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[soranjh]

Thanks @Jaybsoni, looks great. Left some comments and questions. My major point is on the optional support for decomposition of standard PL gates, if they have a decomposition method.

[mudit2812]

Thanks Jay. Is the plan to merge this before the circuit graph PR or after?

[Jaybsoni]

Probably will merge this first and then address that PR afterwards