[FL-2969] FuriHal: add ADC API

[skotopes]

What's new

• FuriHal: add ADC API
• fix #2314

Verification

• Check example_adc

Checklist (For Reviewer)

• [x] PR has description of feature/bug or link to Confluence/Jira task
• [x] Description contains actions to verify feature/bugfix
• [x] I've built this code, uploaded it to the device and verified feature/bugfix

[github-actions[bot]]

Compiled f7 firmware for commit 07bb9f90:

• 📦 Update package
• 📥 DFU file
• ☁️ Web/App updater
• 📊 Size report