[ENHANCE] Add dates to external funding sources

[lachlanglen]

Summary

We are adding optional date to each external funding source

• Project registration form (note how funding sources are stored as JSON string on-chain as plFundingSources) Designs here
• Project detail page (Funding section) Designs here

Motivation

[More detailed explanation of the motivation for the enhancement, including any benefits it would provide]

Description

[Detailed description of the enhancement, including how it would work and any design considerations]

Alternatives

[Discussion of any alternative solutions that were considered and why the proposed solution is preferred]

Risks

[Identification and mitigation of any potential risks associated with the enhancement]

Acceptance Criteria

[List of criteria that must be met for the enhancement to be considered accepted]

Additional Information

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