refactor(templates): Make templates and providers generic

[peterwht]

With the introduction of contract generation, with specific types (ERC, Examples, etc), duplicate code was introduced for Template types (such as Provider and ContractTypes and parachain & contract templates).

This PR introduces two traits to simplify template handling:

• Template -> the types of a TemplateType.
• TemplateType -> the type, category, or "parent" of a Template

For example:
ERC -> TemplateType has many types ERC20, ERC721
Pop -> TemplateType has many types Assets, Contracts, EVM

[codecov]

Codecov Report

Attention: Patch coverage is 76.36364% with 39 lines in your changes missing coverage. Please review.

Project coverage is 70.03%. Comparing base (209024b) to head (fbd9f50).

@@            Coverage Diff             @@
##             main     #226      +/-   ##
==========================================
- Coverage   70.07%   70.03%   -0.04%     
==========================================
  Files          44       44              
  Lines        6596     6565      -31     
  Branches     6596     6565      -31     
==========================================
- Hits         4622     4598      -24     
+ Misses       1236     1230       -6     
+ Partials      738      737       -1     

Files	Coverage Δ
crates/pop-common/src/errors.rs	0.00% <ø> (ø)
crates/pop-contracts/src/templates.rs	97.67% <100.00%> (+7.07%)	⬆️
crates/pop-contracts/src/utils/helpers.rs	78.72% <100.00%> (ø)
crates/pop-parachains/src/errors.rs	0.00% <ø> (ø)
crates/pop-cli/src/commands/mod.rs	0.00% <0.00%> (ø)
crates/pop-cli/src/commands/new/contract.rs	50.00% <80.00%> (ø)
crates/pop-contracts/src/call.rs	69.84% <0.00%> (ø)
crates/pop-contracts/src/up.rs	63.80% <0.00%> (ø)
crates/pop-parachains/src/new_parachain.rs	81.81% <75.00%> (ø)
crates/pop-parachains/src/templates.rs	97.91% <97.77%> (+6.80%)	⬆️
... and 3 more

... and 2 files with indirect coverage changes

[AlexD10S]

Nicely done.
I'm not completely convinced by the name TemplateType, but it seems the best approach to include both providers for parachains and categories for contracts.

[evilrobot-01]

Great start, left a number of suggestions for improvement.

[peterwht]

Comments resolved! Seems much better now :)

[brunopgalvao]

LGTM.

[evilrobot-01]

LGTM!