Feat: Add support for PKCS12 / PFX client certificates for mTLS

[pietrygamat]

Description

This change allows bruno to use client certificates stored in PFX / PKCS12 files in addition to regular PEM cert/key pairs.
Updated the Client Certificate selection in Collection view so that the user can specify if they are using pfx format, in which case the key file becomes unnecessary, and the control disabled. The passphrase field works for both formats.

Axios used by bruno has the support built-in so this change is a rather trivial one, with only the question of UI to solve.

resolves #1889
resolves #1698

Contribution Checklist:

• The pull request only addresses one issue or adds one feature.
• The pull request does not introduce any breaking changes
• I have added screenshots or gifs to help explain the change if applicable.
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

For reference: Postman implementation

[helloanoop]

Thank you @pietrygamat !

@lohxt1 Lets target this to have it merged for next weeks release.
Assigning it to you.

[thalesog]

Guys, can we get this PR merged, please?

[jimbase]

+1 :-) I want to present bruno to my colleagues as the better alternative to postman - but I need the change bc of our client certificates environments

[nddipiazza]

When clicking on the Add certificate button, it says "Successfully added client certificate" but nothing appears in the Client Certificates list

[nddipiazza]

ignore my last comment.
when updating Bruno on windows using the Exe... the exe does not seem to update gracefully
we had to delete %LocalAppData%\Programs\bruno then run the exe to update. then it worked.

[nddipiazza]

adding a +1 from community here. this fixed our problem.