Order button updates

[EngineerCharlie]

I'm just opening this issue to consolidate all the feature adjustments needed for the order button. This consolidates previous issues/code todos.

New features:

• Check user has funds to cover position size, show alert message if not (Order guardrails to prevent fat fingering #50)
• Check user is not using 100% of available xrd (Order guardrails to prevent fat fingering #50)

Feature adjustments/improvements:

• Change price on a limit order is 5% below or above best buy/sell alert to be less intrusive (eg toast) (Order guardrails to prevent fat fingering #50)
• Change slippage greater than 5% alert to be less intrusive (eg a toast) (Order guardrails to prevent fat fingering #50)
• Adjust % button behaviour to put in the requested amount even if there is not liquidity
• Improve wording and information given in trade "description"
• Quickly typing in a percentage position size on the "Buy" side sends a call to fetch balances too quickly. Might need debouncing

Other updates:

• Automatic updating of balances (will be addressed in this issue: bug fix: fetchBalances is not called when the user makes transactions #68)
• Getting best buy/best sell prices (should eventually be addressed by this issue: bug fix: fetchBalances is not called when the user makes transactions #68)
• Implement proper design/styling

[EvgeniiaVak]

fixed by #117