Renamed STRK to FRI

[marioiordanov]

Usage related changes

CLI arguments changes:

gas-price-strk -> gas-price-fri
data-gas-price-strk -> data-gas-price-fri

GAS_PRICE_STRK -> GAS_PRICE_FRI
DATA_GAS_PRICE_STRK -> DATA_GAS_PRICE_FRI

Devnet methods:

In json request/response:
gas_price_strk -> gas_price_fri
data_gas_price_strk -> data_gas_price_fri

Development related changes

Renamed STRK to FRI

Checklist:

• Checked out the contribution guidelines
• Applied formatting - ./scripts/format.sh
• No linter errors - ./scripts/clippy_check.sh
• No unused dependencies - ./scripts/check_unused_deps.sh
• No spelling errors - ./scripts/check_spelling.sh
• Performed code self-review
• Rebased to the latest commit of the target branch (or merged it into my branch)
  • Once you make the PR reviewable, please avoid force-pushing
• Updated the docs if needed - ./website/README.md
• Linked the issues resolvable by this PR - linking info
• Updated the tests if needed; all passing - execution info