fix: offer creation improvements

[TimoGlastra]

Some improvements / cleanup to the credential offer creation process:

• Take the input grants as leading, and only set default values if a required prop is not provided. Currently the grants objects are overwritten in some places, which means that a) you can't add custom properties and b) the authorization_server in e.g. the pre auth flow was removed when the offer was created
• do not put the whole credential offer uri in the credential_offer_uri param, this was leading to weird behaviour where sometimes the value would be the whole uri openid-credential-offer://credential_offer_uri=<uri> and sometimes just <uri>. So now the object just contains the uri that hosts the credential offer, not the uri that is scanned by the wallet (it's quite confusing that the credential offer uri can contain a credential_offer_uri param, so it was somtimes interchanged).
• Correctly encode the credential_offer_uri param (Fixes credential_offer_uri= hosted credential url should be uri encoded in the credential offer #102)

[codecov]

Codecov Report

Attention: Patch coverage is 74.19355% with 16 lines in your changes missing coverage. Please review.

Project coverage is 49.10%. Comparing base (56b16a3) to head (fa2b31b).
Report is 907 commits behind head on develop.

Files with missing lines	Patch %	Lines
...kages/issuer/lib/functions/CredentialOfferUtils.ts	77.77%	10 Missing ⚠️
packages/issuer/lib/VcIssuer.ts	64.70%	5 Missing and 1 partial ⚠️

❗ There is a different number of reports uploaded between BASE (56b16a3) and HEAD (fa2b31b). Click for more details.

HEAD has 11 uploads less than BASE

Flag	BASE (56b16a3)	HEAD (fa2b31b)
	6	0
unittest	6	1

Additional details and impacted files

@@             Coverage Diff              @@
##           develop     #159       +/-   ##
============================================
- Coverage    89.22%   49.10%   -40.12%     
============================================
  Files           17       74       +57     
  Lines          668     4975     +4307     
  Branches       170     1730     +1560     
============================================
+ Hits           596     2443     +1847     
- Misses          69     2529     +2460     
  Partials         3        3               

Flag	Coverage Δ
unittest	49.10% <74.19%> (-40.12%)	⬇️

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[TimoGlastra]

Hey @nklomp do you have a chance to look at this PR this week?

[nklomp]

Looks good. We always use accolades to prevent bugs in case someone had a rough night ;)

[nklomp]

Accolades

[nklomp]

@TimoGlastra Small nudge, since you requested for these PRs to be merged

[TimoGlastra]

done